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田中 太, 黒田 成昭
2001 年 67 巻 660 号 p.
1904-1911
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
We proposed new computational method using Newton-Raphson method for elastic deformation problem by the fluid force in the previous paper. However, the jacobi matrix takes long computational time in that method. In this paper, we propose two new computational methods for jacobi matrix. One is the method that the jacobi matrix Is calculated using a local region of flow field. The other is the method that the jacobi matrix is calculated only from the boundary condition. The new methods shorten the computational time of jacobi matrix drastically. The flow in an elastic tube with a stenosis was calculated numerically as a computational example. The numerical results obtained by the present methods show good agreement with the results obtained by the previous method.
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蔦原 道久, 岡林 雅明, 片岡 武
2001 年 67 巻 660 号 p.
1912-1917
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Effect of the body force in the finite difference lattice Boltzman method (FDLBM) is studied. A simple one-dimensional model is employed, and the error is estimated to be order of the square of the acceleration due to the body force. Spin-up phenomenon is calculated by FDLBM, the lattice BGK model with introducing the Colioris force in the local equilibrium distribution function. The convection terms are discretized by third order up-wind scheme. The spin-up time is compared with the theoretical one, and both agree well.
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富樫 盛典, 岡本 良雄, 宮島 歩, 門向 裕三, 柏谷 峰雄
2001 年 67 巻 660 号 p.
1918-1923
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Liquid injectors are found in many kinds of applications. In this work, we focus on the fuel injector of an automobile engine. It is important to predict the properties of the spray in order to improve the fuel spray pattern of the injector. We selected the spray cone angle and the flow rate distribution among the properties of the spray, and predicted them by numerically simulating the internal flow in the fuel injector. The finite volume method with an unstructured mesh was used in this numerical simulation. The spray cone angle was predicted by extrapolating the velocity vectors at the nozzle outlet. The flow rate distribution was predicted by numerically detecting the number of the flow path lines at the nozzle outlet. Moreover, the numerically simulated spray cone angle and the flow rate distribution agree well with experimentally measured ones.
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木下 利博
2001 年 67 巻 660 号 p.
1924-1929
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
When a circular cylinder is traveled in a towing tank, it has been observed that the wake vortices near the ends begin to be shed at oblique angles at the low Reynolds number. As the cylinder travels further, the oblique shedding region extends inwards and it covers the parallel shedding region gradually. The oblique vortex shedding mode in the circular cylinder wake is examined numerically with the three-dimensional Navier-Stokes simulations. Transition from a parallel shedding mode to an oblique shedding mode is observed for both a free-ended circular cylinder and a circular cylinder with end plates. The present study shows that the different end conditions such as the angle of the end plates result in a distinct oblique angle even if the Reynolds number is the same. The effects of the end conditions upon the mode tansitions and the final oblique angles will be discussed.
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岡本 征雄, 平井 秀一郎
2001 年 67 巻 660 号 p.
1930-1936
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Lattice Boltzmann simulation in two-dimensional porous media has been conducted in order to investigate effect of pore structure on shape factor in capillaric permeability model. Capillaric permeability model that approximates porous media as conduits to bundle of tubes provides permeabilities of Darcy's law. Since deviation from tubes is empirically imposed on shape factor, fundamental study to clarify effects of pore structure on shape factor is of great importance. In this study, a new boundary condition of LBM for arbitrary shape has been applied to various fundamental two-dimensional porous media. Shape factors reflecting pore structure were obtained. Under the conditions that porosity and hydraulic diameter are constant, shape factors are calculated in porous media that elliptic cylinders were arranged in staggered, square and hexagonal grids. Shape factors increased to 3 to 10 in these arrangements. Comprehensive interpretations have been made to elucidate effects of narrow flow path and stagnation on shape factors, which depends on the arrangements of the objects.
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市川 武久, 中林 功一
2001 年 67 巻 660 号 p.
1937-1944
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
To understand the features of axisymmetric separation flows between two parallel disks, we have investigated the rotation effect of upper or lower disk on an inlet separation bubble around the inlet corner and a reverse flow that appears downstream on the stationary disk, using a flow visualization technique and numerical calculation methods. For the case where the upper disk opposite to the inlet pipe rotates, the radius of reattachment point of the inlet separation bubble increases and the reverse flow region enlarges from the outlet to the inlet side, as rotating Reynolds number increases. Then the inlet separation bubble combines with the reverse flow. We have also examined the effect of a radial diffuser on the reverse flow. A ring separation bubble occurs on the stationary disk opposite to the rotating disk when the radial diffuser is put around the rotating disk.
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市川 武久, 中林 功一
2001 年 67 巻 660 号 p.
1945-1951
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
To understand the features of an axisymmetrically rotating separation flow between two parallel disks, we have investigated the rotation effect of counter- and co-rotating disks on an inlet separation bubble which appears around the inlet corner and a downstream flow, using the numerical calculation method. We have also examned the effect of a radial diffuser (stationaly disks) on these flows. The reverse-flow region appears downstream In the mid gap when the disks are counter rotating. Furthemore, the dead-water region appears when the disks are co-rotating. And the radius of reattachment point of the inlet separation bubble varies with an increase of the rotating Reynolds numbers, as the reverse-flow or the dead-water region increases upstream from the outlet. In both cases, a pair of ring vortices rotating counter to each other occurs in the region between the rotating disks, when the radial diffuser is placed around the rotating disks.
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松尾 繁, 島本 克己, 瀬戸口 俊明, 金子 賢二
2001 年 67 巻 660 号 p.
1952-1959
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
A rapid expansion of moist air or steam in a supersonic nozzle gives rise to nonequilibrium condensation phenomena. Thereby, the nozzle flow is affected by the latent heat released by condensation of water vapor. Many papers for the passive control of shock-boundary layer interaction using the porous wall with a plenum underneath have been reported on the application of the technique to transonic airfoil flows. In this paper, this passive technique is applied to a steady condensation shock wave generated in a supersonic nozzle. For the effect of the passive shock-boundary layer control on steady condensation shock, Navier-Stokes equations were solved numerically using a 3rd-order MUSCL type TVD finite-difference scheme with a second-order fractional-step for time integration. As a result, the state of flow field has been clarified.
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奥平 頼道
2001 年 67 巻 660 号 p.
1960-1967
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The Concentric Double Pipe is constructed from two pipes with one end of the inner pipe (inner diameter d
i) reaching to within a distance L from the sealed end of the outer pipe (inner diameter D
i). The sealed end of the outer pipe is constructed from the cap with a curvature (a curvature radius ratio R/D
i, R : a curvature radius) or the plate cap (R/D
i=0). The present paper deals both with a fluid flow issuing from an annulus and turning back into the inner pipe (it is called suction flow). We report the experimental data giving the total head loss through a turning flow region from the end of the inner pipe to the bottom of the outer pipe for two area ratio A
r=0.567, 2.26 (A
r is defined as the cross-section area of the annulus divided by that of the inner pipe) and Reynolds number (R
e=4.8×10
3∼3.6×10
4). The head loss of the cap with the curvature is bigger fairly than that of the plate cap in the range taking the maximum value of the head loss, where the head loss of the cap with the cone is smaller fairly than those of the other caps.
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濱川 洋充, 深野 徹, 西田 英一, 石田 秀樹
2001 年 67 巻 660 号 p.
1968-1974
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The relation between flow induced acoustic resonance and vortex shedding from the tube banks was experimentally investigated. We measured sound pressure level near the duct exit and the vortex shedding frequency, the intensity of velocity fluctuation and the spectrums of velocity fluctuation in the tube banks by using a tube banks model which has same pitch ratio as that of a boiler heat exchanger. We found three types of vortex shedding with different Strouhal number, 0.29, 0.22 and 0.19. The vortex shedding of St =0.29 and 0.22 are generated inside of the tube banks, other one of 0.19 is in the wake of the last row of the tube banks. The velocity fluctuation and the periodicity of the vortex shedding from the second row of the tube banks are the most intense in the tube banks. The amplitude of velocity fluctuation due to the vortex shedding became large in accordance with the generation of the acoustic resonance which has the fundamental natural frequency of the acoustic resonance in the transverse direction of the duct.
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亀田 孝嗣, 大坂 英雄, 望月 信介
2001 年 67 巻 660 号 p.
1975-1982
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The Similarity of the velocity defect profile has been investigated for the turbulent boundary layer over smooth wall, d-type rough wall and k-type rough wall. The velocity defect profiles normalized with the friction velocity u
τ and boundary layer thickness δ are not similar, depending systematically on the wake parameter II. Therefore, a new velocity scale u
o is defined based on the similarity of the wake velocity component for the outer region. The velocity defect profiles normalized with u
o and δ are similar much better with each flow fields, except for the results of a low Reynods number R
θ=960 for the smooth wall flow. These results show that the velocity scale u
o is a proper scale in the outer region for three flow fileds. Then the wake function for each flow fields is succesfully represented by a single curve. In addition, investigating the contorted shape of turbulent bulge, the interval of up and down in the streamwise direction is narrower as II increases, but the width in the transverse direction is almost constant.
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一宮 昌司, 中瀬 敬之, 福富 純一郎, 近藤 誠一郎, 筒井 功
2001 年 67 巻 660 号 p.
1983-1989
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
A turbulence wedge that develops downstream from a single roughness element placed in a laminar boundary layer on a flat plate was experimentally investigated. Streamwise vortices, development mechanisms of the wedge in the wall-normal and spanwise directions and development process of the turbulent quantities in the downstream were clarified. Many streamwise vortices appear within the wedge just behind the roughness. Further downstream, on the other hand, a pair of streamwise vortices are found on both interfaces between the wedge and the outer laminar region. The development mechanism of the wedge in the spanwise direction may be governed by the streamwise vortices ; the mechanism in the spanwise direction is different from that in the wall-normal direction. The fluctuating velocities and the Reynolds stresses just behind the roughness are larger than those of the developed turbulent boundary layer because of the many streamwise vortices. Further downstream, they more closely resemble those in the developed turbulent boundary layer.
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増沢 近統, 平野 雄一郎, 石田 正弘
2001 年 67 巻 660 号 p.
1990-1996
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Reverse flow which occurs in a low pressure steam turbine rotor under the low load operation was analyzed by the three-dimensional turbulent flow computation. The computed flow angles at the inlet and exit of the rotor agreed well with the experimental results in the scale-model turbine and also with the results based on the quasi 3-D inviscid flow analysis. It is clearly shown that the spiral-type vortex appears due to the reverse flow at the rotor root, and in addition, the leading-edge separation occurs on the pressure surface over the rotor blade height, especially a large separation occurs at the root side due to a high incidence angle. The present study suggests that the unstable flow might be caused by the spiral-type vortex and the leading-edge separation under lower load operations.
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本郷 卓也, 高橋 実
2001 年 67 巻 660 号 p.
1997-2004
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
A probe for bubble measurement by the use of infrared laser was developed to investigate the effects of a magnetic field on the dynamic characteristics of bubbles in magnetic fluid two-phase flow in a vertical pipe. The transition condition from bubbly flow to slug flow under non-magnetic field was different from that in the traditional two-phase flow pattern map. When the magnetic field was applied to the magnetic fluid two-phase flow, large bubbles increased and the spaces between bubbles became narrower in the upstream of the position of maximum magnetic field strength. The bubbles were broken into small bubbles near the position of maximum magnetic field strength and the number of the large bubbles decreased in the downstream of the maximum magnetic field strength.
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南葉 正浩, 佐々木 晃, 松内 一雄, 恩田 昌彦, 古井 仁哉
2001 年 67 巻 660 号 p.
2005-2012
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
We examined the drag and thrust efficiency of an airship with a stern propeller. It is supposed that there is a mutual interference between the airship hull and the propeller. To obtain a understanding of the interference, we measured the form drag of airship with and without a propeller, the propeller efficiency and the total efficiency of the airship. Furthermore we carried out inviscid computation for the effect of the propeller on the airship efficiency. It was clarified that the direct ; effect of the propeller on the pressure on the hull surface is weaker than that on the boundary layer separation and also expected that the inviscid flow field would give the best thrust efnciency.
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瀬戸口 俊明, 高尾 学, 板倉 邦輔, 金 太昊, 金子 賢二, 井上 雅弘
2001 年 67 巻 660 号 p.
2013-2018
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
In order to develop an efficient turbine for wave power conversion suitable for the actual ocean conditions, the air turbine with staggered blades has been presented and investigated experimentally by model testing. The experimental investigations have been performed under steady flow conditions. Then, the running and starting characteristics under sinusoidally oscillating flow conditions have been clarified by a computer simulation using a quasi-steady analysis. As a result, it is found that the air turbine with staggered blades is superior to the Wells turbine, and a suitable choice of design factor has been suggested for the setting angle of the rotor.
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倉田 真吾, 村松 将邦, 長谷 隆
2001 年 67 巻 660 号 p.
2019-2026
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The traffic behavior is investigated for vehicles moving in groups (platooning) analytically and numerically. The car-following model of traffic is extended to take into account a binary mixture of vehicles. It is shown that the moving in groups stabilizes the traffic flow. The jamming transition between the freely moving and jammed phases occurs at a higher density than the threshold of the original car-following model. The traffic current is enhanced at a high density region by keeping a short headway. The jamming transition is analyzed with the use of the linear stability method. It is found that the theoretical neutral stability curve is in good agreement with the transition line obtained by the simulation result. It is shown that the moving in groups has a significant effect on the enhancement of traffic current.
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中村 雅英, 志賀 誠, 遠藤 康
2001 年 67 巻 660 号 p.
2027-2033
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Bond graph is a method to simulate the dynamic behavior of mechanical, hydraulic and electric systems from the viewpoint of energy flow. It is well known that this method is effective to the analysis of non-linear systems. In this paper, the bond graph was applied to the analysis of biological flows, i. e., the unsteady flows in the flexible tube with the stenosis, bifurcation and leakage through the wall. The numerical results showed that this method is applicable to the analysis of biological flows and the satisfactory results can be obtained even if the mesh division is coarse enough.
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中村 雅英, 小塚 賢裕, 石塚 正幸
2001 年 67 巻 660 号 p.
2034-2040
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
It is well known that blood denotes the viscoelastic property under the unsteady flow conditions. So, we analyzed the unsteady blood flows through the two-dimensional channel with the fixed stenosis to evaluate the effect of blood viscoelasticity on the distribution of wall shear stress. In this study, we adopted the Thurston model to denote the viscoelastic property of blood. The results are summarized as follows : i) The difference among these models appears clearly in the amplitude of wall shear stress. ii) The results based on the Casson model are in qualitative agreement with the results based on the Thurston model, but the Casson model has a tendency to underestimate the amplitude of wall shear stress compared with the Thurston model.
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宇高 義郎, 王 世学, 小林 大範
2001 年 67 巻 660 号 p.
2041-2047
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
By using the finite differece calculation, the investigation of the configuration of copper heat transfer block were carried out to realize large heat flux for the phenomena having high heat transfer section was trapezoidal and the measuring method of the so-called extrapolation method in which coefficient and the high precision of measurement. The form of the heat tranfer block whose cross-the heat transfer quantities were determined by the measurement of the internal temperature distribution were selected as a subject. Although the relatively large temperature distribution was occurred on the heat transfer surface for the block having trapezoidal section, it was shown that the surface temperature uniformity was realized satisfactorily with the addition of the notches at the edges of the surface. Furthermore, the effects of the geometrical and the thermal non-dimensional parameters were clarified. As a result, the configuration of the block and its ranges of dominant parameters showing the good thermal performance were determined.
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川口 清司, 岡本 義之, 鈴木 昌彦, 真船 利宏
2001 年 67 巻 660 号 p.
2048-2054
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
In recent years, calorific power of semiconductor has been increasing. So more compact cooling unit for high power control panel compared with air-forced aluminum fin is desired. We have been developing the new counter flow type Compact cooling unit having inclined radiation fin. In this paper, we have established the simple method for calculation of cooling performance of heat exchanger by using radiation fin modeled by pressure resistance in the flow field, and by using NTU method in the temperature field.
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川口 清司, 真船 利宏, 鈴木 昌彦, 岡本 義之
2001 年 67 巻 660 号 p.
2055-2061
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
In recent years, calorific power of semiconductor has been increasing. So more compact cooling unit for high power control panel compared with air-forced aluminum fin is desired. We have been developing the new counter flow type cooling unit having inclined radiation fin. In this paper, we have established the calculation method of cooling performance of the cooling unit having the heat exchanger modeled by pressure resistance, considering air velocity distribution at the inlet of the heat exchanger generated by cooling fan.
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麓 耕二, 山岸 英明, 福迫 尚一郎
2001 年 67 巻 660 号 p.
2062-2067
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
This study deals with the critical heat flux of ice accretion along a horizontal fine wire immersed in cold air stream with water spray. Experiments are carried out to investigate the effect of droplet diameter, wire diameter, air velocity and air temperature on the critical heat flux. Present results reveal that critical heat flux is markedly affected by both the droplet diameter and the wire diameter. In this study, the effects of four parameters (droplet diameter, wire diameter, air velocity and air temperature) on the critical heat flux are quantitatively determined, and a non-dimensional empirical equation that correlates the critical heat flux and above parameters has been obtained.
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谷川 洋文, 増岡 隆士, 小松 直樹, 井上 達哉
2001 年 67 巻 660 号 p.
2068-2074
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
This study is concerned with the method of control of thermal convection in a horizontal fluid layer by utilizing a shape memory screen consisting of a row of shape memory alloy plates with two-way shape memory effects. Experimental and numerical results show that the shape memory screen, which brings about the change of flow resistance with temperature, brings about the transition from large-scale convection to local-scale convection. It is found that the shape memory screen can reduce the average Nusselt number and cause thermal oscillation.
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白樫 了, 酒井 康行
2001 年 67 巻 660 号 p.
2075-2080
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
Vitrification is one of the ideal methods for cryopreserving cells and tissues. Most of the vitrifying solutions of low toxicity and high vitrifying ability are macromolecules, which do not permeate cell membranes. In the present study, enhancement of membrane permeability by electroporation is discussed. Membrane permeability of human hepatomas (HepG2 cells) to several macromolecules (600-70 000 Da) was measured with laser confocal fluorescent microscopy (LCMS). It was found that under the experimental condition, the membrane permeability of HepG2 to the given molecules is aslarge as 10
-8 m/sec, and the membrane permeability scarcely affected by the strength of electric field.
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光武 雄一, 門出 政則
2001 年 67 巻 660 号 p.
2081-2088
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
An experimental study of transient heat transfer during cooling of a hot cylindrical block with an impinging water jet has been done at atmospheric pressure. The internal block temperatures and the radius of wetted region were measured for the following conditions : a fixed initial block temperature of 250°C, a degree of subcooling of 20-80 K, a jet velocity of 5=15 m/s, a fixed nozzle diameter of 2 mm and three block materials of copper, brass and carbon steel. Heat transfer on the surface consisted of single-phase convective heat transfer, annular nucleate boiling and film boiling. The radius of the wetting front, which bounds the nucleate boiling region and the dry region, was well correlated with a power function of time. The maximum heat flux along the radial direction occurred on the moving nucleate boiling region. It also compeared with the critical heat flux at steady state. In the case of a good heat conductor such as copper which is capable to supply enough large heat to the surface, the maximum heat flux was comparable with the CHF. Reversely that for a poor amount of conductor was significantly limited below the CHF.
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伊藤 定祐, 高野 靖, 三浦 直勝, 内川 靖夫
2001 年 67 巻 660 号 p.
2089-2096
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The cooling performance of the heat pump system in which an air-cooled and a water cooled condensers were arranged in a series was studied experimentally and analytically. The capacity of the compressor was 250 W and R22 was used as the refrigerant. In the analysis, the coefficient of performance (COP), the cooling power, the heat absorbed by the air and the heat absorbed by the water at the condensers were predicted using the data of the heat pump with the air-cooled condenser and the heat pump with the water-cooled condenser. The COP was able to be increased by using the air-heat source in addition to the water heat-source. Also, the thermal load of the water heat-source became half by adding the air heat-source in the system when the temperature of the water was 5°C higher than that of the air.
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植草 常雄, 柳 正秀, 君島 真仁, 河合 素直
2001 年 67 巻 660 号 p.
2097-2104
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The air conditioner which cools telecommunication equipment rooms or computer rooms must operate throughout the year. So we apply refrigerant pump cycle to the air conditioner to improve coefficient of performance (COP) at low outdoor air temperature. At first, this paper discusses two kinds of control methods. One is superheat control to manipulate refrigerant pump frequency. Refrigerant pump cycle controlled by this method can operate higher efficiency than that controlled by expansion valve. The other is room air temperature control method to manipulate air flow rate = of condenser. Next, this paper discusses year round electric consumption comparison with conventional air conditioner. The electric consumption of the air conditioner with refrigerant pump is 50% shorter than that of conventional air conditioner.
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稲葉 英男, 木田 貴久, 堀部 明彦, 亀田 澄広, 岡本 民雄, 徐 貞均
2001 年 67 巻 660 号 p.
2105-2112
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
This paper has dealt with water vapor sorption characteristics of powder type organic sorbent bed by flowing a moist air. The powder type sorbent was fluidized in a rectangular vessel by the moist air flow. The sorption rate of vapor and the variation in temperature in the sorbent bed were measured under various air temperature and humidity conditions. It was found that the volume of the sorbent particles increased with in an increase in the amount of water vapor sorption. Finally, Sherwood number for water vapor mass transfer was expressed in terms of Reynolds number, the modified Stefan number, the ratio of sorbent particle diameter to fluidized bed height and Schmidt number.
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稲葉 英男, 松尾 幸一, 堀部 明彦
2001 年 67 巻 660 号 p.
2113-2120
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
The present paper has dealt with the natural convection heat transfer in a melted liquid layer appeared in the inclined rectanglar latent heat storage vessel having one heating wall with plate fins. The effects of plate fin length, inclination angle of the rectangular vessel and heat wall temperature on the melting behavior of paraffin wax as a latent heat storage material. and natural convection heat transfer were investigated experimentally under a heat storage process. As a result, non-dimentional correlation equations of natural convection heat transfer were derived in terms of some non-dimentional parameters.
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若林 英信, 羽田 哲, 纐纈 尚人, 牧野 俊郎
2001 年 67 巻 660 号 p.
2121-2128
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
A new spectrophotometer system is developed for the study on thermal radiation phenomena of real surfaces. This system can measure spectra of reflection and emission of radiation at 93 wavelength points in the near-ultraviolet through infrared region of λ=0.30∼11μm on one system simultaneously and repeatedly with a cycle time of 2s. The system is applied to investigate the transition of spectra of reflection and emission of a metal surface in a high-temperature air-oxidation process. It is demonstrated that interference and diffraction behavior, which is caused by the change in microstructure of the surface, is clearly observed as simple and systematic change of the spectra over the wide spectral region. The ability of the developed system for the study on radiation phenomena is demonstrated. It is also suggested that a real-time technique can be developed on the basis of the performance of the developed system to diagnose the temperature and microstructure of real surfaces.
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船津 徹也
2001 年 67 巻 660 号 p.
2129-2134
発行日: 2001/08/25
公開日: 2008/03/28
ジャーナル
フリー
In combined cycle start up operation, the faster start up while maintaining steam tubine thermal stress under the limitation is requested. This paper presents an optimum start up algorithm for combined cycle, using model predictive control algorithm. The steam temperature inside steam turbine is estimated by using developed simulator, and modeled by ARX method. The Rotor temperature and thermal stress are predicted using the steam temperature ARX model. The gas turbine loading rate is determined by predicting the thermal stress sequentially. The result shows the thermal stress is precisely restrained under the thermal stress limitation while reducing the start up time about an hour from the conventional method.
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千田 二郎, 田中 智之, 廉 廷國, 芦田 耕一, 藤本 元
2001 年 67 巻 660 号 p.
2135-2140
発行日: 2001/08/25
公開日: 2008/03/28
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フリー
This study is dealing with a simplified attempt for evaporation process of multi-component fuel sprays. KIVA-II scheme was used as a multi-dimensional numerical code. And new conceptual model on multi-component fuel spray evaporation was proposed based on a simplified approach of two-phase region in vapor-liquid equilibrium. In the model, 50% distillation temperature of each component fuel was applied into evaporation process of multi-component solution, instead of precise estimation of two-phase region characteristics. Then, spatial vapor distributions of each fuel component were assessed from this model calculation in KIVA-II scheme.
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原田 明, 浅海 靖男, 青柳 友三
2001 年 67 巻 660 号 p.
2141-2144
発行日: 2001/08/25
公開日: 2008/03/28
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フリー
Recently, pre-mixed lean mixture combustion has attracted attention, and many researchers are investigating compression ignition of a pre-mixed lean mixture. Previous research in our laboratory has shown that low NO
x emission combustion is obtained by PREDIC (PREmixed lean Dlesel Combustion) . However some problems still remain, such as higher fuel consumption because of lack of ignition timing control, compared to conventional diesel combustion. So in this study the ignition ; characteristic was researched. As the result, it was cleared that the ignition timing was depended on the cylinder gas temperature and the ignitability of the fuel.
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畠山 収司, 村山 正, 関谷 芳男, 中井 俊作, 佐古 孝弘, 常本 秀幸
2001 年 67 巻 660 号 p.
2145-2150
発行日: 2001/08/25
公開日: 2008/03/28
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フリー
Small two stroke SI engines with supplying natural gas in the intake port are advantageous for long maintenance duration and low cost when applied the co-generation and heat pump system for residential use. But in the engine port injection system, the unburned HC emission is higher and thermal efficiency is lower than that of 4 stroke engines. To overcome these disadvantages, the in-cylinder injection with special low pressure injection nozzle system was attempted. The results showed that the improvements of unburned HC emission and thermal efficiency are possible due to the remarkable reduction of scavengjng loss and the lean combustion.
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