-
中村 育雄
1989 年 55 巻 512 号 p.
929-935
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
-
加賀 拓也
1989 年 55 巻 512 号 p.
936-943
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The results of an experimental investigation on a two-dimensional cavity flow around a circular cylinder are presented based on the data processing by a time series analysis, as well as statistical method, and a flow visualization by a high-speed camera. A relation between unsteady flow patterns and unsteady fluid forces is discussed. Under some conditions of a frothy cavity, strong and periodic oscillations are observed for the forces exerted on the circular cylinder. The periodic oscillation occured at the time when the straight line cavity boundary behind the circular cylinder and a cavity termination were at the same position.
抄録全体を表示
-
渡辺 久志, 山田 正俊, 今井 健二, 石井 美也, 佐々木 忍
1989 年 55 巻 512 号 p.
944-950
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Recently, high pressure injection systems have been widely adopted in diesel engines. However, many problems have arisen. One of them is cavitation erosion in the fuel injection system. This erosion is very harmful to the performance and reliability of the engines. A new approach different from the steady flow approach is employed to study this unsteady cavitation phenomenon. In this study, the cavitation phenomenon is clarified by measurement of the pressure, fuel velocity and cavity, and calculation of the axial distribution of the pressure and cavity volume. The method of predicting the degree of erosion is investigated by the injection characteristics. It is clarified that the degree of erosion is well predicted by the overall value of the high frequency alternation contained in the injection pressure.
抄録全体を表示
-
花村 庸治, 山口 和夫, 平野 孝典, 鈴木 和富
1989 年 55 巻 512 号 p.
951-959
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
An experimental investigation is carried out on the aerodynamic interblade interactions and the aerodynamic damping of the carcade using a Freon gas wind tunnel by means of the one blade oscillation method for the high turning turbine cascade in the transonic flow. Unsteady moment and normal force are measured during the pitching vibration. The reason why the aerodynamic damping of the cascade tends to the negative in higher Mach numbers with a strong shock wave is clarified in consideration of the variation of the center of the unsteady force with Mach number.
抄録全体を表示
-
〓崎 展, 市原 稔章
1989 年 55 巻 512 号 p.
960-966
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Rotating stall in a vaneless diffuser was studied and predicting equations of rotational speeds of stall cells were presented in a previous paper by the authors. For a prediction of the rotational speeds of cells using the predicting equations, a tangential component of the time-averaged flow velocity at an impeller exit should be known. However, there is no general method for calculating the tangential velocity at the impeller exit under rotating stall of a vaneless diffuser. The difference of impeller performance is not clear between rotating stall and steady flow conditions. In this paper, an operating condition of a centrifugal impeller under rotating stall of a vaneless diffuser is described from measurements of characteristic curves, pressure distributions in the impeller channel and flow conditions near the impeller exit.
抄録全体を表示
-
藤原 義也, 富田 侑嗣, 上滝 具貞
1989 年 55 巻 512 号 p.
967-971
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Capsule motion was numerically analyzed by the method of characteristics for the case when a single capsule was transported through a pneumatic horizontal straight pipeline having a release valve at the end of a branch pipe. Two types of boundary conditions at the pipe inlet were used, that is, the pressure being constant and the mass flow rate of air being constant. The effect of the air release position in the pipeline on the capsule exit velocity and the time required to go through the line were examined. when the inlet pressure was constant, the effect of air release on the exit velocity increased with the tank pressure but the effect on the required time decreased with the tank pressure. When the mass flow rate was constant, the effect on both increased with the mass flow rate.
抄録全体を表示
-
須藤 浩二, 高見 敏弘
1989 年 55 巻 512 号 p.
972-977
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Friction coefficients have been made clear for turbulent flows through curved square pipes with rough surfaces. An experiment has been carried out under the conditions of the equivalent relative roughness ke/d=3.15×10
-31.94×10
-2, Reynolds number Re<5×10
4 and the curvature radius ratio Rc=15 and 25. The approximate expression, which expressed the experimental results well, was derived using the theory of the boundary layer.
抄録全体を表示
-
宮内 敏雄, 斉藤 拓也
1989 年 55 巻 512 号 p.
978-984
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The aim of this study to clarify the 3-dimensional coherent structure in turbulent shear flows and the effect of a streamwise vortical structure on the turbulent mixing. To achieve this purpose, large eddy simulation of a turbulent shear flow with a passive scalar mixing was conducted. As an initial value, a 3-dimensional small perturbation was overlapped on the mean velocity profile. From the calculated results, the following conclusions are obtained. (1) The 3-dimensional perturbation develops into a streamwise counter rotating vortex pair. (2) The growth rate of the 3-dimensional instability is slower than that of the 2-dimensional instability. (3) The growth rate is maximum when the spanwise wavelength of the 3-dimensional perturbation is two thirds of the streamwise wavelength of the fundamental wave.
抄録全体を表示
-
原口 荘太郎
1989 年 55 巻 512 号 p.
985-990
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Each of the two-type turbulent flows with the different inlet conditions were introduced to a conical diffuser and its downstream outlet pipe. The velocity profiles, distribution of turbulence intensities and turbulence shear stress of each flow were measured at many sections. The effects of inlet conditions are apparent in the diffuser and in its downstream region of about 10 times the outlet pipe diameter from the outlet of the diffuser. Each flow reaches a fully developed stage at the downstream section of about 65 times the outlet pipe diameter from the outlet of the diffuser.
抄録全体を表示
-
西島 勝一
1989 年 55 巻 512 号 p.
991-998
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Turbulent square-duct flow is studied numerically using an anisotropic k-ε model in which the deviation of the Reynolds stress from its isotropic eddy-viscosity representation plays a central role. The noslip boundary condition on the wall is satisfied with the aid of a wall damping function. Various computed turbulent quantities of square-duct flow are compared with experimental and numerical results. This comparison shows that the present anisotropic k-ε model can give reasonable result to important properties in duct flows such as the anisotropy of turbulent intensities and the secondary flow.
抄録全体を表示
-
三宅 裕, 梶島 岳夫
1989 年 55 巻 512 号 p.
999-1007
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Turbulent channel flow is numerically simulated by the large eddy simulation (LES) technique. A finite difference scheme with about 3.83 million grid points is applied to the case of a Reynolds number of 5840. Turbulence statistics are compared with the experimental data and the results of the recent large scale computation. Agreements are quite reasonable. Numerical results are stored as a data base for the purpose of studying turbulence structure and the modeling in the near-wall region. as the first report of the series of the work, this paper presents the balance of each term in the transport equations of the turbulence kinetic energy, the dissipation rate and the Reynolds stress tensor.
抄録全体を表示
-
長野 靖尚, 田川 正人, 新美 幹夫
1989 年 55 巻 512 号 p.
1008-1015
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
An improvement of the k-ε model has been made in conjunction with an accurate prediction of the near-wall limiting behavior of turbulence and the final period of decay law of free turbulence. The present, improved k-ε model has been extended to predict the effects of adverse pressure gradients on shear layers, which most previously proposed models failed to correctly predict. The proposed model was tested by application to a turbulent pipe flow, a flat plate boundary layer, a relaminarizing flow, and a diffuser flow with a strong adverse pressure gradient. Agreement with experiment was generally very satisfactory.
抄録全体を表示
-
近藤 継男, 長野 靖尚
1989 年 55 巻 512 号 p.
1016-1021
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Flows behind a backward-facing step were simulated by directly solving the Navier-Stokes equation. The calculated time-mean flow field was compared with the well-appraised experiments, and good agreement was obtained. In addition, from the detailed information given by the calculation, the structure of the separating and reattaching flow was investigated. It was found that the unsteady "flapping" motion of the reattachment point is the reflection of the vortex structure which is present in the separating shear layer.
抄録全体を表示
-
坪内 邦良, 吉田 正平, 菱田 公一, 前田 昌信
1989 年 55 巻 512 号 p.
1022-1029
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The presence of particles or water droplets in the flow of turbomachinery, especially in the low pressure stages of a wet steam turbine, leads to the erosion on the moving blades and causes the increase of energy loss. Therefore, there is a growing demand for measuring the behavior of these particles directly in order to evaluate and prevent the blade erosion. This report is concerned with the measuring technique of droplet sizing and velocity in the atomized droplet flow by a four-beam fiber optic LDV system. The optical system makes two coaxial volumes with different diameters and droplet sizes are evaluated by light scattering intensity. The results of experimental calibration using a monodispersed droplet generator with the vibrating orifice indicate good agreements with those of microscopic measurements. Finally, this paper shows the results recorded in the atomized droplet flow at different chamber pressures.
抄録全体を表示
-
田部井 勝稲, 白井 紘行
1989 年 55 巻 512 号 p.
1030-1034
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A numerical method is presented for inverting the moire data which represent integral light deflection to internal temperature and /or density distributions. The method is applicable to both symmetrical and asymmetrical flow field. The inverting method is constructed on the basis of the Maldonado-Olsen series representation which was developed for the inversion of an integral intensity fields. The validity and accuracy of the present method have been demonstrated by using a mathematical model with a density function of a truncated pyramid type.
抄録全体を表示
-
田部井 勝稲, 白井 紘行, 町田 けい子
1989 年 55 巻 512 号 p.
1035-1038
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
In order to demonstrate the validity and applicability of the moire-schileren method for asymmetrical flow fields, temperature distributions have been measured in a diffusive combustion flame with a rectangular nozzle. Experimental moire images of the flame, which show integral light deflection, were recorded by a video camera, and were inverted to an internal temperature distribution by the numerical inverting method based upon the modified Maldonado-Olsen series representation. The results show that the temperature profiles in the flame have a complex feature caused by a rectangular nozzle and the resent inversion method is very effective.
抄録全体を表示
-
鳴海 敬倫, 細川 喜弘, 長谷川 富市
1989 年 55 巻 512 号 p.
1039-1044
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The reverse squeezing low of dilute polymer solutions has been studied utilizing a flat plate and a spherical surface of a large radius of curvature. In this experiment, both surfaces are forced to separate by applying constant forces from a stationary and contacting state. All the liquids used are Newtonian in viscosity. The following points are found by comparing the results of inelastic liquids and viscoelastic liquid. In the case of the viscoelastic liquid, the surfaces separate from each other much more slowly than in the case of the inelastic liquid. This trend is clearly shown when the separation is small. The results predicted by the theory of inelastic fluids with the assumption of the quasi-steady state agree well with the experimental results. The same assumption, however, cannot explain the slow separation effect because of a small contribution of elastic terms.
抄録全体を表示
-
沈 能耀, 辻 裕, 森川 敬信
1989 年 55 巻 512 号 p.
1045-1053
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
An experimental study has been made of particle motion and the minimum gas velocity to transport particles in a vertical pipe. Particles with different properties (material, diameter and shape) were used in the experiment. A measuring system based on a video camera and image processing computer were used to record particle trajectories. Experimental results show that the particle-wall collision is the most influential factor for the particle motion even in the vertical pipe flow. it was also found that the particle concentration is closely related to particle shape and the coefficient of restitution.
抄録全体を表示
-
梅垣 菊男, 三木 一克
1989 年 55 巻 512 号 p.
1054-1061
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A numerical method is developed to solve the two-dimensional incompressible viscous flow with rotating boundaries of arbitrary shape using the boundary-fitted curvilinear coordinate transformation technique. The stream function-vorticity formulation is developed in which the requirement of the single-valuedness of the pressure is explicitly included to determine the boundary values of the stream function. The method is verified by the analysis of the flow between two long, eccentric cylinders. The method is also applied to the transient flow analysis in which the flow is driven by arbitrarily shaped rotating blades, and it is confirmed that the flow patterns can be successfully simulated using the proposed method even if the system has a moving boundary.
抄録全体を表示
-
吉野 章男, 林 達夫, 若 良二
1989 年 55 巻 512 号 p.
1062-1067
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The boundary value of the stream function on a body in a two-dimensional flow fluctuates when the flow is unsteady. The value must be given suitably to the flow when the flow, expressed by stream function and vorticity, is numerically solved by the finite difference method. The authors proposed the method of automatically pursuing the appropriate boundary value of the stream function on a body without using any empirical parameter, as a method of satisfying the single value condition of the pressure term of the equations of motion. This method is successfully applied to the calculation of the uniform shear flow around a rotating circular cylinder. The result of calculation shows that this method is applicable to both the steady and unsteady flows without using any empirical parameter.
抄録全体を表示
-
高見 敏弘, 須藤 浩三, 富田 幸雄
1989 年 55 巻 512 号 p.
1068-1077
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A developing laminar flow of power-law fluids in the entrance region of curved pipes has been investigated by analyzing the three-dimensional elliptic equation numerically and measuring velocity profile with an optical fiber LDV. The flow mechanism from the curved pipe inlet to the fully-developed region has been made clear under the condition of the power index n> 0.6, two curvature ratios Rc=10 and 30, and Dean number De=100500. As the power index decreases, the primary flow becomes more highly distorted and the axial velocity profile with double peaks appears on the symmetry plane in the initial development. Also, the secondary flow grows drastically at the inlet adjacency and declines rapidly to form another vortex pair in a part of developing region.
抄録全体を表示
-
須藤 浩三, 高見 敏弘, 島田 伸和, 檜原 秀樹
1989 年 55 巻 512 号 p.
1078-1084
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Experimental investigation has been made of free jets issuing from three curved nozzles, which are 90° circular bend with a diameter 40 mm and curvature radii of 80, 160, and 240 mm. Mean and fluctuating velocities are measured by the method of rotating a probe with an inclined hot wire. The following conclusions are derived from the experimental results: (1) The jet axis shifts from the curved nozzle axis, and the shifting distance is longer as the curvature radius of the nozzle is smaller; (2) The maximum axial velocity of the curved nozzle jet decays more rapidly than that of a straight nozzle jet; (3) The spread of the jet is almost independent of the curvature radius; (4) The velocity profiles are skewed by a secondary flow near the curved nozzle and become gradually smooth towards the downstream.
抄録全体を表示
-
高昌 伸, 鮎川 恭三, 渡辺 福寿
1989 年 55 巻 512 号 p.
1085-1090
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Peristaltic pumping in an symmetric two-dimensional channel with one fixed wall and one moving wall is investigated experimentally for a wide range of amplitude ratio, and for Reynolds numbers ranging in order from unity to 10
3. Measurements of the mean pressure rise and of the mean flow are carried out, and the interdependent relations between them describing the primary properties of the pumping performance are discussed. It is found that for zero mean flow, the pressure rise is independent of Re for a small Re, while it increases proportionally to Re
1/2 for a large Re. However, the relations between the pressure rise and the mean flow are approximately linear for large Reynolds numbers as well as for small Reynolds numbers.
抄録全体を表示
-
岡本 史紀, 松永 勝秀
1989 年 55 巻 512 号 p.
1091-1096
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
This paper describes an experimental study of the flow past a square cylinder of finite length placed on a ground plane. The experiment was carried out in an N.P.L. blowdown-type wind tunnel having a working section of 500 mm×500 mm×2000 mm in size at the Reynolds number 2.5×10
4. The surface pressure distributions on the square cylinder were measured and the drag coefficient was determined from them. The vortices of two kinds generated in the flow field around a square cylinder have also been observed. As a result, it was found that the flow pattern changes rapidly at height-width ratio H/D=7, changing the shedding vortices from arch type to Karman type.
抄録全体を表示
-
増田 渉, 五十嵐 雅人, 白石 和彦
1989 年 55 巻 512 号 p.
1097-1100
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Small signal gain coefficients of a supersonic flow CO chemical laser are measured using a shock tunnel facility. A high temperature mixture of CS
2, CS, S
2, S and Ar is produced in a shock tube, where the thermal dissociation of CS, diluted in Ar is accomplished by a reflected shock wave. The shock-heated mixture is exhausted through two-dimensional supersonic nozzles mounted at the end of the tube and mixed with the supersonic streams of O
2. Then, the vibrationally excited Co molecules are produced in the mixed streams. In the present paper, the dependence of the small signal gain coefficients on the downstream distance from the nozzle, the plenum conditions and the transition branch is studied. The data obtained in the present experiments are available to examine the propriety of the theoretical model which was developed previously.
抄録全体を表示
-
増田 渉, 平出 弘之
1989 年 55 巻 512 号 p.
1101-1108
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Small signal gain coefficients of a supersonic flow CO chemical laser are calculated using a theoretical model which was developed previously and compared with the corresponding experimental results. It is shown that the model predicts the gain characteristics only qualitatively. The measured small signal gain coefficients are considerably small compared with the calculated results. In the present investigation, the theoretical model is improved significantly by modifying the relaxation rate constants and including the effects of the boundary layers which develop in the test section. However, further improvement on the theoretical model is necessary by including the effects of the nozzle boundary layers and shock waves.
抄録全体を表示
-
竹永 久邦, 倉元 靖夫, 福田 征孜, 藤川 貞爾
1989 年 55 巻 512 号 p.
1109-1114
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A series of tests such as nozzle single tests, blade single tests and single stage turbine tests have been conducted to put a hot water turbine to practical use. A hot water turbine is considered to be very useful for waste heat recovery plant and geothermal power plant etc. In this 1st report, both theoretical and experimental results of Laval nozzles which are used to obtain a high speed two-phase uniform flow from a hot water are described. It is shown both theoretically and experimentally that nozzle inlet pressure, assist steam quantity and droplet size have large influence upon two-phase flow nozzle performance. Some typical photographs of Laval nozzle exit flow are shown.
抄録全体を表示
-
西山 哲男, 馬目 俊文, 黒沢 貞男, 太田 照和
1989 年 55 巻 512 号 p.
1115-1123
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The resent paper proposes a three-dimensional boundary element method based on velocity potential for a swept turbine cascade spanning parallel walls in which the flow turning angle is very large. The local aerofoil characteristics over the span-surface pressure distributions, circulation, aerodynamic force-and furthermore, the local flow characteristics in the outlet-trailing vortex strength, outlet velocity, turning angle are clarified in close relation to swept angle and aspect ratio. In particular, the three-dimensional flow behaviour in the vicinity of up and downstream end of the span are examined. Lastly, the present method is confirmed to be appropriate by comparisons with Gothardt-Stark's experimental results. The cosine rule is also clearly demonstrated to hold true for the swept turbine cascade.
抄録全体を表示
-
段野 勝, 朝倉 俊行, 島田 貢明, 部谷 尚道
1989 年 55 巻 512 号 p.
1124-1128
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
When an electropneumatic valve positioner is surrounded by combustible gas, the electrical control circuit should be located far from the actuator of the valve by connecting them using a long pneumatic tube to provide the greatest degree of safety. Then, if the length of the pneumatic tube exceeds a certain length, the actuator will occur hunting oscillations due to the time lag of the pneumatic pressure signals. The magnitude of this time lag is in accordance with the tube length, tube diameter and capacity of the actuator. This report investigates the step and frequency responses to define such a time lag theoretically and compares it with experiments carried out in foreign countries together with a discussion on it. As the result, the theoretical results of the step response agreed approximately with the experimental ones. The frequency response also agreed with them except for the phase lag in the case of the long tube. The studies on the valve positioner are being carried out using these results.
抄録全体を表示
-
今井 良二, 辻本 良信 /, Allan J. Acosta
1989 年 55 巻 512 号 p.
1129-1136
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Separated flows in a centrifugal impeller are analyzed by using a singularity method on the assumption that the absolute flow is two-dimensional, steady, imcompressible, inviscid, and irrotational. By using an iterative method, the boundary conditions on the surface of separated region is applied exactly on the surface; a non-linear theory. From the angular momentum relations, it is shown that the most reasonable flow is obtained in the case when the separated region terminates with a cusped form. The velocity field and the pressure distributions are given for various flow rated and assumed separation points. The decrease in head is larger for upstream separation. Over/under filing effects are discussed by applying the present method on the assumption that the flow is separated at the trailing corners of thick vanes.
抄録全体を表示
-
宮本 弘之, 中嶋 幸敏, 安永 義博, 白木 和晟
1989 年 55 巻 512 号 p.
1137-1141
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Flow measurements were made in an unshrouded centrifugal impeller running at 1000 rpm. The impeller has 10 blades which are two-dimensional and radial at the outlet. for a flow rate in the shockless inlet to the blade, the relative velocities and the reduced static pressures were measured on nice cross-sectional planes within the rotating impeller passage, using a five-hole pressure probe fixed on the impeller-hub-wall. The rotary stagnation pressures were calculated from the measured values of the relative velocities and the reduced static pressures. In the mid-passage of the impeller, the wake due to the effects of the turbulent mixing, the Coriolis force, the curvature of the passage, the tip clearance flow and the friction on the casing wall, is shown about mid-position between the suction and pressure surface near the casing. The wake region increases on the suction surface at the outlet of the impeller, because of the turbulent mixing due to the uniformity of the pressure.
抄録全体を表示
-
古川 明徳, 戸越 勉, 佐藤 紳二, 高松 康生
1989 年 55 巻 512 号 p.
1142-1146
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
It is known that a head breakdown of centrifugal pumps in a two-phase flow occurs at a gas/liquid ratio less than ten percent, due to gas accumulations in the impeller. If these accumulations could be evacuated by use of an impeller with multiple tandem blades, two-phase flow pumps might be operated at a higher gas/liquid ratio. Tests to examine the effects of a tandem-bladed impeller on the pump performance in single-phase and two-phase water/ air flows are described. Experimental results in comparison with results of an unsplit impeller thow that there is no difference of the pump performance in a single-phase flow between both impellers, and a two-phase head degradation in a flow region with elongated bubbles is improved at large water flow rates.
抄録全体を表示
-
井土 剛一, 中村 育雄
1989 年 55 巻 512 号 p.
1147-1152
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Particle transportation by fluid motion is a very familiar phenomenon in nature and also important for various industrial application, for example, the transport of crops, coal, sand and other materials. An investigation is reported in this paper on the motion of a sphere falling through water with or without spin. The sphere used was made of Teflon in 1-inch diameter and having a very smooth surface. The sphere falls with spin driven by a gearmotor mechanism, or without spin. The motion of the sphere was recorded by a camera and the trajectory was analyzed to obtain the acceleration and drag and lift coefficients C
D and C
L. The motion was very irregular but C
D and C
L showed reasonable values and the results can be used for fluid transportation engineering.
抄録全体を表示
-
瀬戸口 俊明, 金子 賢二, 濱川 洋充, 井上 雅弘
1989 年 55 巻 512 号 p.
1153-1158
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The biplane Wells turbine for a wave power generator has many special merits. However, it has hysteretic characteristics in a reciprocating flow, which results in an inaccurate prediction of the performance in a quasi-steady analysis. In order to clarify the hysteretic characteristics, an experimental investigation has been carried out by the use of a sinusoidal axial flow. The results have shown that hysteresis is less sensitive to the gap to chord ratio and more sensitive to the solidity and arrangement of the biplane rotor. By means of flow visualization, the relation between the hysteretic characteristics and the behavior of a wake has been discussed.
抄録全体を表示
-
瀬戸口 俊明, 金子 賢二, 濱川 洋充, 井上 雅弘
1989 年 55 巻 512 号 p.
1159-1163
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Experimental investigations directed towards improving the overall characteristics of the turbines for wave power generators are reported. Biplane axial turbines with variable setting angles have been manufactured and tested to investigate the effects of the blade setting angle, gap to chord ratio, solidity and arrangement of biplane rotor on the turbine performance. The results have been compared with those of the air turbine with self-pitch-controlled blades and biplane Wells turbine. A suitable choice of the design factors has been suggested.
抄録全体を表示
-
本田 逸郎, 大庭 英樹, 中嶋 幸雄, 安田 正夫, 松本 晋弥, 須藤 幸雄
1989 年 55 巻 512 号 p.
1164-1167
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The establishment of a design method of a rotary vane compressor for an automotive air conditioner is described. When the suction pressure is high. The detachment of the vane from the cylinder wall occurs under a particular condition. In order to avoid this phenomenon, the authors have been performed many experiments. However, the experimental studies requise much time and cost. Accordingly, a numerical simulation is available for solving this problem. The method and result of a computer simulation for the force acting on the vane is described in this paper.
抄録全体を表示
-
椎林 正夫, 東條 健司, 池川 正人, 村山 朗
1989 年 55 巻 512 号 p.
1168-1173
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
In order to the predict performance of scroll compressors, it is important to estimate both mechanical losses and gas compression power. The mechanical losses are mainly due to the stirring forces of the refrigerating oil and frictional forces between moving parts. It is necessary to under stand the influence of the oil on the compressor for improving the accuracy of performance prediction. In this study, sealing effects and cooling effects of the refrigerating oil, which have not yet been studied sufficiently, are discussed. As a result, the effects of the refrigerating oil on the compressor performance and cooling characteristic are clarified.
抄録全体を表示
-
数土 幸夫, 薄井 徹, 神永 雅紀
1989 年 55 巻 512 号 p.
1174-1180
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The effects of gap size on heat transfer characteristics were investigated experimentally for a vertical rectangular flow channel with a gap of 2.5 mm, 6 mm and 18 mm. As a result, the following was revealed. Flow shows the nature of forced convective heat transfer when Gr
x/Re
21/8xPr
1/2 is less than 2.5×10
-4, and the nature of free convective heat transfer when Cr
x/Re
21/8xPr
1/2 is higher than 1.8×10
-3, commonly for three gaps of flow channel. As for the data with a gap of 2.5 mm in the transition region between forced convection and free convection, it was confirmed that the higher heat transfer coefficient than that predicted by a heat transfer correlation for turbulent forced convection along a flat plate was owing to the acceleration of the main flow by the development of the boundary layer, not to buoyancy force.
抄録全体を表示
-
田島 守, 牧 忠, 片山 功蔵
1989 年 55 巻 512 号 p.
1181-1187
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
An experimental and numerical investigation of the generated latent heat of phase transformation to several carbon contents of steel during quenching was performed. The problem of unsteady heat conduction accompanying the phase transformation was solved by using the apparent heat capacity method. The experimental and calculated cooling curves to several carbon contents of steel when the initial temperature was 700°C and the values of thermophysical properties of S 45 C carbon steel agreed well. The thermophysical properties of S 45 C carbon steel applied widely to the carbon content of steel below 1 percent. Experimental results of the temperature and the latent heat of phase transformation of S 55 C and SK 5 carbon steels could be explained by using the cooling rate at the temperature of A
1 transformation. The phase transformation of several carbon contents of steel was expressed only the carbon percent. The cooling curves calculated using these expressions for initial temperature of 850°C agreed well with the experimental results.
抄録全体を表示
-
横野 泰之, 佐々木 富也, 石塚 勝
1989 年 55 巻 512 号 p.
1188-1193
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The effect of a cubic obstacle above small rectangular fins on the natural air cooling performances was experimentally investigated, varying the clearance between the fin tip and the obstacles, the fin height and the fin interspacing parametrically. The heat dissipation capability of a fin was diminished under the critical clearance which was not significantly affcted by the fin height and the fin interspacing. Through the flow visualization, natural convection flow pattern was not altered by the clearance, the fin height and the fin interspacing. It was found that the correlations of the fin cooling performances and the clearance were not reversed by altering the fin height.
抄録全体を表示
-
吉川 英夫, 高橋 秀俊, 郡 正治, 松井 愃
1989 年 55 巻 512 号 p.
1194-1198
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
LiAlO
2 in the Lithium complex oxide materials is considered and evaluated as the most effective candidate material for the blanket of the TOKAMAK fusion reactor. This paper discusses the establishment of an analytical model in order to estimate the corrosion thickness of the SUS 316 austentic stainless steel which is used as a structural material, and the diffusion coefficient derived from the experimental results of a Secondary Ion Mass Spectrometer.
抄録全体を表示
-
金 潤植, 品川 祐一, 吉川 邦夫, 程 永元, 塩田 進
1989 年 55 巻 512 号 p.
1199-1205
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A two-dimensional unsteady heat transfer analysis in the combustion chamber of a pebble bed regenerative heat exchanger for high temperature argon heating has been performed for the evacuation and argon heating periods. The analysis well explains the measured time history of the temperature of the top of the pebble bed facing the combustion chamber during both periods. The analysis also shows that optimization of the height of the combustion chamber is important for maximizing the argon temperature at the exit of the heat exchanger.
抄録全体を表示
-
金 潤植, 吉川 邦夫, 品川 祐, 塩田 進
1989 年 55 巻 512 号 p.
1206-1211
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
A heat transfer analysis code for predicting the performance of a regenerative heat exchanger for high temperature argon heating has been developed which simulates heat transfer processes in the combustion chamber coupled with those in the storage bed of a pebble bed. The thermal performance of heat exchangers under cyclic operation is predicted by this code, and the results show that optimization of geometries for both the combustion chamber and the heat storage bed is important for improving the thermal performance. Unsteady response of heat exchangers to the change of the external load of a closed cycle MHD electrical power generator is investigated by the computer code. The results show that the response time is almost the same as the cyclic operational period of heat exchangers.
抄録全体を表示
-
五味 光男, 藤井 昭一, 金井 美一
1989 年 55 巻 512 号 p.
1212-1216
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The accuracy of simplified CARS (Coherent Anti-Stokes Raman Spectroscopy) temperature measurements has been studied. The proposed CARS method provides the instantaneous temperature determination with the quick measurement of the intensity ratio of N
2 CARS spectra by the use of a specially prepared monochromator, two photomultipliers and data processor including a circuit for sampling mechanism, an A/D converter, and a personal computer. Various causes and their contributions to the measurement errors introduced in these instruments have been evaluated experimentally. In the static hot air experiment, the standard deviation characteristic of the total error was 55 K for the mean temperature 928 K and 1000-shots. It is recommended that 500 laser-shots be used in order to obtain a reasonable mean temperature.
抄録全体を表示
-
上出 光志, 工藤 一彦, 谷口 博, 佐山 惣吾, 行道 覚, 阿部 淳一
1989 年 55 巻 512 号 p.
1217-1223
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The effects of several factor that affects the ignition temperature of solid fuels were measured by using simulated fuel and an air-flow type thermobalance. For the simulated fuel, a mixture of activated charcoal, salicylic acid bentonite was used to simulate the fixed carbon, volatile matter and ash of solid fuels. The fuel could simulate solid fuels with a wide range of component ratios. The newly designed air-flow type thermobalance gave uniform oxygen supply within the fuel layer. The experimental parameters were oxygen concentration (0-100 vol%), gas flow rate (8-300 cm
3/min) and fuel component ratio. Based on the results, it can be concluded that: (1) the ignition of solid fuel is initiated by the ignition in the mixture of volatile matter and air, and there is an optimum volatile matter-air ratio for the ignition, (2) the ignition temperature is estimated by excess oxygen ratio in the fuel layer and oxygen concentration in the feed gas of solid fuel.
抄録全体を表示
-
浜本 嘉輔, 吉山 定見, 冨田 栄二, 泉 政明
1989 年 55 巻 512 号 p.
1224-1228
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
The behavior of turbulent premixed flame was investigated by using a small ion gap in a closed vessel. Considering that ionization is strongly related to the combustion reaction, the analysis of ion-current wave yields the characteristics of turbulent flame structure. The main results are as follows: (1) The time scale of the ion current obtained in turbulent flame decreases with an increase in turbulence intensity. (2) The length scale of the ion current is nearly constant within the range of turbulence intensity in this experiment. (3) The fluctuation of the flame front produced by the turbulence is observed by analyzing the ion-current wave, and the change in the fluctuation versus the turbulence intensity is similar to the change in the roughness of turbulent flame front observed with flame photography.
抄録全体を表示
-
冨田 栄二, 浜本 嘉輔, 佐々木 洋
1989 年 55 巻 512 号 p.
1229-1233
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Instantaneous heat flux to the wall of a combustion chamber was measured by a co-axial thermocouple with a thin fin junction for the case with laminar and turbulent flame of a propane-air mixture. The experiment was performed in a constant volume vessel of the disk-type with swirl flow. When the laminar flame arrived at the wall, the heat flux had one sharp peak. In the case of the turbulent flame, however, the heat flux with multiple sharp peaks was observed. It is considered that this phenomenon corresponds to the structure of the turbulent flame. The maximum value of peak heat flux, q
max is approximately proportional to {k(T
i-T
u)/δ
L}
0.61, where (T
i-T
u)/δ
L is a characteristic value of the temperature gradient in a preheat zone of laminar flame and k is the heat conductivity. The same relation is obtained, even when the flow velocity, equivalence ratio or measuring position are varied.
抄録全体を表示
-
村瀬 英一, 小野 信輔, 花田 邦彦, 仲原 彰治
1989 年 55 巻 512 号 p.
1234-1240
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
In order to confirm quantitatively the performance and characteristics of the plasma jet ignition in turbulent lean mixtures, combustion tests were carried out with varying the governing parameters of the plasma jet ignition. three plasma cavity sizes of 37, 75, and 170 mm
3, three orifice diameters of 1, 2, 5 and 4 mm, and three discharge energies of 0.3, 0.6 and 0.9 J were tested in a disk-shaped combustion bomb with lean methane-air mixtures. A characteristic lifetime and a characteristic length of the plasma jet and an entrainment volume of the mixture into the plasma jet were defined theoretically and expressed by the parameters of the plasma jet igniter. From a series of combustion test, the lean flammability limit, the comparing parameter, and a combustion index are well correlated with these characteristic values, where the comparing parameter shows the degree of combustion enhancement by the plasma jet ignition in its initial stage and the combustion index represents the total combustion performance of the plasma jet ignition.
抄録全体を表示
-
吉田 茂徳, 原 人志, 岡島 敏
1989 年 55 巻 512 号 p.
1241-1247
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Experiments were conducted to study the combustion behavior of a fuel droplet array under microgravity. The effect of the ambient pressure on the flame propagation was investigated. Also the fundamental characteristics such as the flame propagation velocity and its mechanism were obtained. The results show that there are three different patterns of flame propagation, which depend on the ambient pressure and droplet spacing, as follows: 1) The flame propagates smoothly along a fuel droplet array. 2) The flame propagates intermittently. 3) The flame propagates in an extremely intermittent manner, where two adjacent unburnt fuel droplets are ignited at almost the same time. In every case, the flame propagation velocity can be calculated and it is found that it continues to decrease rapidly with increasing ambient pressure.
抄録全体を表示
-
石田 正弘, 吉村 良孫, 植木 弘信, 泉 修平, 吉武 政浩
1989 年 55 巻 512 号 p.
1248-1252
発行日: 1989/04/25
公開日: 2008/03/28
ジャーナル
フリー
Cylinder pressure is measured simultaneously at several points in the combustion chamber of a high speed diesel engine with a toroidal piston cavity by means of small-sized piezo pressure transducers and a multichannel combustion analyzer with an accuracy of one fourth degree of crank angle. It has been clearly shown on the cylinder pressure behavior that the farther the distance of measuring point from the cavity center, the latter the rapid pressure rise and the larger the pressure fluctuation amplitude. The time difference of the rapid pressure rise between two measuring points is identical to the propagation time of a pressure wave originated in the piston cavity. The peak frequencies in the cylinder pressure spectrum, which correspond to the two kinds of wavelengths of cylinder bore and two times the root mean square diameter, are due to standing waves in the combustion chamber.
抄録全体を表示
