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Seiji SHIMIZU, Atsushi YAMAGUCHI
1987 Volume 53 Issue 493 Pages
2697-2702
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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A discrete-vortex method is used to simulate a two-dimensional turbulent free jet. The analysis is made to predict the mean pressure and the rms of the fluctuating pressure distributions in the flow field and trajectories and pressure histories of fluid particles which imitate cavitation nuclei. It is found that the fluid particles released from a point near the jet exit corner experience minimum pressure in a region beyond the potential core of the jet or in the shear layer within the flow-establishment zone.
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Ryuji IKEDA, Yukio ITO, Yoshitaka SHOJI
1987 Volume 53 Issue 493 Pages
2703-2708
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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To make clear the effects of curvature on cavitation characteristics of right-angled branch ducts, the cavitation aspects and the associated change in the branch loss coefficient were carefully and systematically investigated in several kinds of right-angled branch ducts with square cross-sections, for several radii of curvature on the corners, cavitation numbers and flow ratios. Clearly the cavitation aspects and the incipient cavitation numbers and significantly affected by the curvature, while the branch loss is scarecely affected by cavitation for any curvature in the near-subcavitating range defined from the inception range to the transient one.
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Toshio TANAKA, Eiichi TANAKA, Yoshihiro INOUE, Masanori MORISAKI
1987 Volume 53 Issue 493 Pages
2709-2713
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An experimental study has been made on the control of the reattachment of a radial turbulent wall jet through comparatively wide spaced two parallel disks, with an additional control flow. Static pressure distributions along the side wall and the opposite wall, and also across the jet flow were measured with half disk type and a disk type pressure holes. The effects of opposite wall height (distance of opposite wall surface from the nozzle center plane) and control flow rate (ratio of control flow rate to main jet flow rate) on the flow pattern through tow parallel disks were investigated. The position of reattachment to the side wall surface, and pressure at this depend mainly on the combination of the opposite wall height and the control flow rate.
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Takehiko YANAGIDA, Nobuo KAWASAKI
1987 Volume 53 Issue 493 Pages
2714-2719
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Pressure drop of axial air flow through an annulus with a rotating inner cylinder was experimentally studied The results obtained are as follows : (1) When the outer cylinder surface is smooth, secondary flow called Taylor-vortexes occurs in the annular gap. Using a dimensionless number X=Re
2a/R
w (Re
a : Reynolds number, R
w : rotating Reynolds numbers ; Both number are based on hydraulic diameter.), the friction factor λ can be expressed by λ=2.2X
lt;-1/2> (X<
= 5000), and λ=0.072X
-0.1 (X >
= 5000) (2) When the outer cylinder surface is deep-slotted, secondary flow occurs in the sloths. The friction factor can then be expressed by λ=3.25X
-1/2 (X< 4000), and λ=0.275X
-1/5(X> 4000).
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Masaaki OKUBO, Yukio ISHIBASHI, Shuzo OSHIMA, Ryuichiro YAMANE
1987 Volume 53 Issue 493 Pages
2720-2727
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An analysis was made on a laminar flow of the magnetic fluid between two parallel plates with a low speed traveling magnetic field, using Shliomis' and Glazov's equations. The velocity profile, the mean velocity and the coefficient of friction were calculated for the flow with and without a pressure gradient, and compared with the author's previous experimental results and analytical values in a steady magnetic field. The induced flow was in the same or opposite direction to the magnetic field depending on α
1 and the strength of the applied current. The increase in the coefficient of friction was appreciable in a low Reynolds number range and for relatively strong, high frequency current.
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Seiichi SUDO, Hiroyuki HASHIMOTO, Akihiko IKEDA
1987 Volume 53 Issue 493 Pages
2728-2732
Published: September 25, 1987
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The surface tension of a magnetic fluid subjected to a magnetic field tangential to its surface was measured. The surface tension of water-based magnetic fluid decreased with increases in the mass concentration on the constant strength of the external field. On the contrary, however, the surface tension of kerosine-based magnetic fluid increased. The surface tension of magnetic fluid increased slightly with the strength of magnetic field. The interfacial tension between nonmagnetic and magnetic fluids was measured. The interfacial tension also increased with the external field. Based on the measurements of the surface tension, the deformation of a drop of magnetized liquid in a magnetic field was investigated. The elongation of a magnetic drop was measured. The experimental results were compared with the theoretical values determined by the minima of energy.
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Shigeomi CHONO, Yoshiyuki IEMOTO
1987 Volume 53 Issue 493 Pages
2733-2738
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Viscoelastic flows are experimentally studied using two-dimensional L-shaped channels. Velocity and pressure distributions have been measured for various Reynolds numbers and for various channel widths on the downstream side in order to clarify the cause and the conditions under which the reverse flow is generated upstream of the re-entrant corner. The present experiment shows that the reverse flow is largest in size when the Reynolds number is nearly equal to unity and the channel width downstream of the re-entrant corner is a quarter of that upstream of it. Pressure distributions on the channel wall rise in the flow direction in the upstream vicinity of the re-entrant corner. This pressure rise takes the maximum in value and in extent under the same conditions as the reverse flow. It is considered that the normal stress effect, peculiar to viscoelastic fluids, causes the generation of the reverse flow and the pressure rise upstream of the re-entrant corner.
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Takaaki MORIMUNE, Naomichi HIRAYAMA
1987 Volume 53 Issue 493 Pages
2739-2744
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The suitability of the analysis of the unsteady flow through the exhaust junction plays an important role in developing a computer program for matching a diesel engine to an exhaust turbocharger. This paper describes an improvement of the calculation procedure for computing the behaviour of the unsteady gas flow at the exhaust junction. Measured values of pressure, temperature and mass flow rate are compared with computer predictions using four different pipe junction computations : a constant pressure model, a momentum model, a simplified model and the improved exact model developed in this study. This comparison shows that the new technique gives the best agreement with the measured values, while the computer time required is twice as long. Under unsteady flow conditions the exhaust junction gives six types of flow configuration, and calculations indicate only some of these types of flow dominate, and the rest occur for only short intervals.
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Yukio TOMITA, Toshio YOKOYAMA, Shin USAMI
1987 Volume 53 Issue 493 Pages
2745-2749
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Turbulent friction factors of dilute aqueous solutions of polyethylene oxide measured in a two-dimensional channel. The influence of viscoelasticity on friction loss is considered by the method of dimensional analysis and the friction factor is correlated with the Reynolds number and the Weissenberg number. Velocity distributions also are measured by using a pitot tube. It is shown that the transition layer in the flow of dilute polymer solutions becomes thicker in comparison with that of Newtonian.
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Hitoshi NAKATANI, Atushi NAGATA
1987 Volume 53 Issue 493 Pages
2750-2755
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The mean thrust generated on flexible plates oscillating sinusoidally about the front end of plates arranged side by side has been investigated experimentally. Experiments were performed in water flowing at a constant speed and in both cases where the phase angle of two plates is 0° and 180°, the frequency of translation varies from 0.64 to 1.09 Hz and the amplitude of motion from 20° to 60°. Reynolds number based on the plate length is from 8.9×10
3 to 1.2×10
4. Flexible test plates are made of phosphor bronze and their dimensions are aspect ratios of 2:1, 3:1, 10:3 and 11:3 against widths of 30 mm and 60 mm. The thrust was measured by means of wire balances. The effect of four parameters, that is, frequency, flexibility, amplitude and phase angle, on thrust was examined.
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Kohzaburo NAKABAYASHI, Naoyuki YOSHIDA, Tyusei AOI
1987 Volume 53 Issue 493 Pages
2756-2761
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Numerical solutions of the Navier-Stokes equations for viscous shear flows past an infinitely long circular cylinder are obtained for Reynolds numbers ranging from Re=1 to Re=40. The shear parameters, ε's investigated for each Re are 0.01, 0.05, 0.1, 0.2, 0.5 and 1. The outer boundary condition of the free stream is replaced by adding to a linear shear flow Oseen's exact solution for the perturbation stream function that has been obtained in the questions of the uniform flow, and the stream function, Ψ
s, on the surface is decided by imposing a condition that the pressure is single-valued. Numerical solutions for the drag, lift, moment and pressure distributions are presented, and their dependence on the shear parameter are investigated. The most interesting result is that lift gives rise to minus even in this Reynolds number range. Lastly, flow patterns are shown for Re=20.
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Tadao FUJIWARA, Shuji NISHIHARA, Koji HIROSE
1987 Volume 53 Issue 493 Pages
2762-2770
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Color flow-visualization photography and digital image processing techniques have been developed for the purpose of flow measurement in the flow field of a circular vessel with recirculation flow. The pathlines of aluminum powder were photographed on a color reversal film by illuminating it in red, white, and green in turn within an exposure time. The pixel values in red, green, and blue for 256 steps prepared by the drum-scanner as the digital image data of the film, the resultant stimulus and trichromatic coordinates of each pixel were evaluated from them. The pixels for pathlines were distinguished from the background by the threshold-level of resultant stimulus, and their colors were determined by using the principal component obtained from combined and standardized residuals for the regression formulas of trichromatic coordinates. The velocity vectors can be derived from both the location and color of pixels, and the time interval of white color illumination.
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Koichi TSUZUKI, Toshiki IINO
1987 Volume 53 Issue 493 Pages
2771-2776
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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A numerical simulation of dilute gas-particle flows is developed. Turbulent dispersion and Brownian motion of particles are calculated stochastically in the simulation. For calculation of the turbulent dispersion, determination of the time step for integrating the equation of particle motion is crucial, and several ways to determine the time step are examined. Finally, the simulation is applied to calculations of the particle dispersion in flows in cleanrooms.
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Eiji HASEGAWA, Moriyoshi TAMURA
1987 Volume 53 Issue 493 Pages
2777-2784
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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When a jet stream containing the small particles impinges on a plane wall, the particles are possible to collide with the wall. Under the assumption that the flow is incompressible and irrotational, the fluid is governed by stokes drag law, and the interaction between particles is neglected, the classification of various types in the collision between the particles and the wall, the critical conditions above which the particles collide with the wall, the extent of the region in which the collision arise, the distribution of the collision frequency along the wall, the ratio of collision particles to total of particles, the position at which the collision frequency becomes maximum and so on are found theoretically by choosing the stokes number and the angle between the axis of the jet and the wall as the parameters.
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Nengyao SHEN, Yutaka TSUJI, Yoshinobu MORIKAWA
1987 Volume 53 Issue 493 Pages
2785-2790
Published: September 25, 1987
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The scattering of coefficients of restitution and friction, which is often observed in experiments is studied numerically by using a new bouncing model. This model can be applied to the bouncing of particles of arbitrary shape. Numerical simulation shows that the scattering is largely affected by particle shape and that irregular bouncing and Stick-Slip phenomena of particles in horizontal pneumatic conveying are explained by the present model.
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Yasushi TOKUNAGA, Atsushi KOSHIO, Tsuyoshi HASHIMOTO, Masataka SHIRAKA ...
1987 Volume 53 Issue 493 Pages
2791-2799
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The power loss in pipe junctions was measured for a snow/water mixture under the condition of a constant Reynolds number referring to the joined condition. The results are summarized as follows. (1) When the power loss coefficient ζ
c is defined by taking the snow/water mixture as a homogeneous fluid, the relationship between ζ
c and the flow rate ratio Q
2/Q
3 is similar to that for pure water, and the configuration factors, the areal ratio m and the connecting angle θ, have the same effects on the ζ
c∼Q
2/Q
3 relation as on the flow of pure water. (2) When the snow volume fraction C is smaller than the critical value C', ζ
c is equal to that of pure water ζ
cw. When C >C', the presence of snow increases ζ
c, and this effect is more remarkable under a condition with a smaller ζ
cw, i.e., when θ is small and the velocity ratio U
2/U
1 is around unity. (3) An empirical formula is obtained to predict the additional power loss due to the mixing of snow in combining flow.
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Masayuki TAKEISHI, Kotohiko SEKOGUCHI, Hideo SHIMIZU, Masao NAKASATOMI
1987 Volume 53 Issue 493 Pages
2800-2806
Published: September 25, 1987
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This paper describes an investigation of liquid lump velocities in vertical upward gas-liquid two-phase flow. Velocities of individual liquid lumps, such as liquid slugs, huge waves, disturbance waves or ephemeral large wave are determined by a computer-aided data-processing method ; that is time-varying cross-sectional mean liquid holdups are electrically detected at two axially separated locations of the tube, and each liquid lumps from the two holdup signals recorded on magnetic tape. It is demonstrated how the mean values of liquid lump velocity and its standard deviations depend on the gas and liquid flow rates and the related flow patterns. Furthermore, histograms of liquid lump velocity and the statistical relation between wave height and velocity are presented.
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Kotohiko SEKIGUCHI, Masayuki TAKEISHI, G. COGNET, Takakazu ISHIMATSU, ...
1987 Volume 53 Issue 493 Pages
2807-2813
Published: September 25, 1987
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The results of an experimental investigation of liquid lump behaviors are presented for vertical upward gas-liquid two-phase flow. Liquid lumps were classified into liquid slug, huge wave, disturbance wave and ephemeral large wave by analysing time-spatial signals of cross-sectional averaged liquid holdup, which were detected at twelve locations along a 25.8mm inside diameter tube. Two types of behaviors were found for liquid slug and huge wave : one shows axilly steady movement, and the other is transient as a liquid slug rapidly disappears or drastic deformation of a huge wave occurs with time. An evaluation method for the development of cap bubble flow in liquid slug coalescence is proposed. There exist various behaviors of ephemeral large waves such as forward, backward and complicatedly direction-changing movement depending on the flow conditions. It is shown how these behaviors correspond to reverse flow length of liquid film and averaged gas length.
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Koji KIKUYAMA, Kiyoshi MINEMURA, Yutaka HASEGAWA, Mitsukiyo MURAKAMI
1987 Volume 53 Issue 493 Pages
2814-2823
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Pressure distribution and cavitation inception near the inlet region of an impeller passage of a centrifugal pump were examined experimentally. Both at flow rates lower and higher than normal, the pressures on the blade surface of the impeller fluctuated nearly periodically with its circumferential position due to the non-uniform pressure distribution of the volute and the presence of the dividing ridge of the volute. From the measured pressure distributions on the blade surface at a fixed circumferential position, the pressure fluctuations were also found to be caused, especially at low flow rates, by turbulent fluctuations including the separation of flow from the blade surfaces. The quasi-periodic changes in the pressure distribution caused circumferential non-uniformity of the cavitation occurrence near the cavitation inception and effects of the pressure fluctuations on desinentcavitation number were found to be noticeable at a low flow rate.
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Pingdoug WU, Ato KITAGAWA, Toshio TAKENAKA
1987 Volume 53 Issue 493 Pages
2824-2828
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The dynamic characteristics of the poppet valve with series restriction chokes, which used as a directional/flow control valve, have been studied. By using the mathematical model, which includes several nonlinear terms, the dynamic response of the valve was precisely estimated. It was also shown that the volume of the load circuit considerably affects the dynamic response of the valve. A stable condition of the circuit was obtained from the linearlized equations of the model, and its validity was confirmed by the experimental results.
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Yu SESHIMO, Masao FUJII, Goro YAMANAKA
1987 Volume 53 Issue 493 Pages
2829-2834
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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A new concept on the enhancement of forced-convection heat transfer at a Reynolds number lower than 3000 is presented. A new surface has many holes and is bent in a trapezoid shape. The phase of each adjacent surface is changed by half a period, and therefore a duct constructed with these surfaces has enlargement and contraction parts alternately along the flow passages. The heat transfer coefficient of the new duct increased by about three times that of a duct with plain surfaces at the same Reynolds number.
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Sadanari MOCHIZUKI, Yoichi OHTA
1987 Volume 53 Issue 493 Pages
2835-2841
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An experimental study was conducted to determine the fluid flow and heat transfer characteristics in the passage formed by two parallel rotating disks. The local heat transfer coefficients along the disk radius were measured in detail and the flow patterns between the two rotating disks were visualized using a laser-light-sheet method. It was disclosed that (1) the self-sustained laminar flow separation which is characteristic of stationary disks still exists even when the disks are set in motion, and it affects the heat transfer remarkably. (2) For small source flow Reynolds number, Re, and large rotational Reynolds number, Rew, rotating stall dominates the heat transfer. (3) Heat transfer for steady laminar flow exists only when both the source-flow and rotational Reynolds numbers are relatively small : Re < 1200 and Rew < 20.
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Shigeki HIRASAWA, E.G. HAUPTMANN
1987 Volume 53 Issue 493 Pages
2842-2848
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An analytical study was conducted of the contact angle of an evaporating liquid film on a heated wall, which is the most important factor in determining the critical heat flux to cause film breakup. Steady profiles of a rivulet flowing down a vertical heated wall were calculated numerically considering surface roughness. As the liquid film was assumed to the adsorbed o the non-evaporation region, the maximum inclined angle of the liquid film was taken to be the apparent contact angle. The relations among the apprarent contact angle, the inclined angle of the surface roughness and the temperature difference between the wall and the vapor were calculated. When the temperature difference was 5°C, the apparent contact angle of a R113 rivulet was 23°and it was located where the film thickness was 3μm. The apparent contact angle increased in proportion to the temperature difference. The analytical results agreed well with the previous experimental data.
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Toshihisa ISHIDA, terushige FUJII, Koji AKAGAWA, Kazunori HASHIMOTO
1987 Volume 53 Issue 493 Pages
2849-2856
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An analysis of the stability of natural circulation in a closed loop with an inverse U-shaped cooler was performed. The loop consists of an inverse U-shaped tube cooler heating boxes and connecting bent pipes. The calculate flow at a steady state was obtained by one-dimensional analysis using a simplified loop model of the test loop. Stability of the natural circulation flow was studied by linear stability : the flow was investigated by linearized equations to determine whether perturbation of the temperature and the flow rate added in the steady state flow would grow or diappear. Nyquist criterion was used to predict the stability limit. The curves for neutral stability were obtained as a function of the two parameters, non-dimensional cooler heat flux and non-dimensional flow rate, for the various elvation differences between the cooler and the heater. The effect of experimental parameters on the flow stability was studied. The comparison between analysis and experiment showed favorable agreement.
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Katsumi SAKITANI, Yoshio SAHARA, Hiroshi HONDA
1987 Volume 53 Issue 493 Pages
2857-2862
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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An experimental study has been made of the performance characteristics of a natural circulation cooling/latent heat storage system. The system, which consisted of an outdoor condenser, an indoor evaporator and an indoor latent heat storage unit connected by a pipeline, was designed to cool a shelter in which electronic equipment was installed, without using a power source. Lauric acid and refrigerant R-22 were used as the latent heat storage medium and the heat transport medium, respectively. Natural convection heat transfer performance of the outside surfaces of the condenser and the evaporator (cross fin coils) and the transient behavior of the system during the melting and solidification periods of the latent heat storage medium were tested. It was shown that the system can maintain room temperature within the shelter below 50°C even when the shelter was located in an inland area near the equator.
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Masataka SATO
1987 Volume 53 Issue 493 Pages
2863-2868
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The capacity of negentropy is the maximum negentropy that a system can have. For example, the negentropy contained by a cylinder-piston system becomes larger as the piston is moved inward, but practically it has a maximum, namely, the capacity of negentropy. Generally, capacity represents a certain type of macroscopic order (capacity-type of order) which comes from the relation between molecules, and without this type of order, negentropy cannot beheld by a system. Capacity-type of order is regarded as a pattern which has the property of recovering its origin in thermodynamic situations, and the order may be destroyed by negentropy which exceeds the capacity. Although nonequilibrium-type of order, which is represented by negentropy, differs from the capacity-type of order, they are intimately related with each other. The general definition of the capacity is made in a statistical-mechanical manner based on negentropy defined by Kullback-Leibler information.
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Heikichi KUWAHARA, Wataru NAKAYAMA, Tadakatu NAKAJIMA, Hiromichi YOSHI ...
1987 Volume 53 Issue 493 Pages
2869-2873
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The experiments of nucleate boiling heat transfer from porous surfaces were conducted in a pool of saturated R-11. The system pressure was varied in the range of 0.04-0.48 MPa. The porous structure in this investigation is composed of internal cavities in the form of tunnels, small pores, and small ribs under the pores. Compared to the performance of the previously developed surface, the new surface yields a marked enhancement of heat transfer at wall superheats of less than 2K and at a low system pressure of 0.04 MPa. Also reported is the importance of the size of the ribs which are designed obstruct the flooding of tunnels by incoming liquid.
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Masatake YOSHIDA
1987 Volume 53 Issue 493 Pages
2874-2883
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Optimum Ignition Timing is defined as the Minimum Advance for Best Torque (MBT) experimentally. However the relations between the Optimum Ignition Timing and the heat release rate, wall temperature, combustion heat of the mixture, compression ratio, etc. have not been formulated clearly. The problem of this formulation is to integrate the work done on the piston explicitly, because a cylinder volume is not defined as a simple formula of the crank angle. The author presented a simple polynomial of the crank angle for the cylinder volume. Using this polynomial, the author derived the Optimum Ignition Timing formula of the cooled engine as a function of the wall temperature, heat release rate, compression ratio, engine speed, mixture strength, etc.
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Myurng-hoan BAE, Takeyuki MAMIMOTO, Haruki KOBAYASHI
1987 Volume 53 Issue 493 Pages
2884-2889
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The effects of pressure and temperature on soot formation in premixed propane-oxygen-inert gas combustion are reinvestigated over the pressure range of 0.4 to 5.8 MPa and the temperature range of 1000 to 1800 K by using a specially designed disk-type constant volume combustion bomb. The soot concentration in the chamber centre during the final stage of combustion at the highest pressure is measured by the in situ laser extinction method. It is found that the soot yield in lower temperatures rises sharply with increasing pressure, but the dependence of pressure gets weaker with higher temperatures, and that the pressure and temperature during the soot formation mainly influence the soot yield.
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Kazunori SATO, Kunio OKIURA, Akira BABA, Kazunori SHOJI, Iwao AKIYAMA
1987 Volume 53 Issue 493 Pages
2890-2895
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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The main purpose of our study is to delineate the effect of Coal Water Mixture (CWM) properties on spray characteristics and to obtain the necessary data required for optimum burner design. Several experiments on the atomization of CWM will be carried out with twin fluid atomizers. The effect of CWM properties and atomizer type and conditions on the mean sizes and the size distribution of CWM sprays are investigated in detail. It is found that spray droplets become more ununiform in size as the concentration of CWM increases, and that minute droplets are more deformed and big ones are spherical. It is also found that for the Newtonian or pseudo plastic CWM the mean droplet size of CWM spray is almost the same as that of water with an Internal Mixing Atomizer, but is a little larger with a Half Mixing Atomizer.
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Eiji TOMITA, Yoshisuke HAMAMOTO
1987 Volume 53 Issue 493 Pages
2896-2901
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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A turbulent entrainment burning model is considered to be a reasonable one for the combustion in a spark-ignition engine. The concept is based on the Blizard and Tabaczynski model. It is important to estimate the turbulence characteristics, turbulent burning velocity, flame surface area and several experimental constants. Nevertheless, the examination of these values are insufficient, regardless of using many assumptions in previous studies. In this study, turbulence characteristics, the initial stage of burn duration and turbulent burning velocity were discussed in detail. This model was examined under various conditions of engine speed (600-1200 rpm), compression ratio (3.2-4.8) and ignition timing. The calculation results of mass fraction burned, burn rate and burn duration were in good agreement with the experimental ones. It was found that this model was valid for predicting the combustion in a spark-ignition engine.
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Atushi SAITO, Kazuo MASUI, Hiroshi KOMURA, Yasuo SUGIURA
1987 Volume 53 Issue 493 Pages
2902-2907
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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In this second report, both the injector structure and the injection characteristics of the new injection system were firstly investigated by means of the calculation method described in the first repotrt. Then, adequate methods to minimize the power necessary to drive the injection system were investigated and clarified in order to improve fuel consumption more than a conventional fuel injection system.
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Yoshiharu TSUJIKAWA, Teruo SAWADA, Masanobu HIRANO, Yujiro TSUKAMOTO
1987 Volume 53 Issue 493 Pages
2908-2914
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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In supersonic aircraft engines with higher flight Mach number, the temperature of suction air is raised considerably by aerodynamic heating, which causes the degradation of such engine performances as the thermal efficiency and specific fuel consumption. If liquid hydrogen is used as fuel, cryogenic heat can be utilized to precool the suction air. In the present study, the effects of precooling by liquid hydrogen is estimated, considering the ideal precool cycle. The characteristics of the real engine cycle are also investigated. The configuration of the precooler has affected the cycle characteristics. The optimum configuration, therefore, is determined by adopting the new exergy efficiency based on the second law of thermodynamics.
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Yoshiharu TSUJIKAWA, Teruo SAWADA, Makoto NAGAOKA, Yujiro TSUKAMOTO
1987 Volume 53 Issue 493 Pages
2915-2920
Published: September 25, 1987
Released on J-STAGE: March 28, 2008
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Many works on gas turbine engines contain much information concerning the performance of various engine schemes both in simpler and in more complicated forms. Such information enables the design performance to be estimated, but there appears to have been very little works on the optimum performance under non-design conditions. In this paper, we attempt to include a comparison of part load performance characteristics and to optimize them. The multiplier method is adopted as an optimization procedure. As a result of this work, it is possible to indicate the optimization technique by which the comparable part load performance of different gas turbine schemes may be assessed.
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