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Fujio NAGAO, Takasi KOBAYAKAWA
1951 Volume 17 Issue 62 Pages
1-5
Published: 1951
Released on J-STAGE: March 28, 2008
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Fuel air mixture, completely evaporated and mixed in a closed vessel, was ignited at one end by an electric spark. Recording the arrivals of the flame front at the fixed points on the way of its propagation by the use of electric conductivity of the flame, the locus and velocity of the propagation have been found out. At the same time variations of the combustion pressure were recorded on the same oscillogram. The experiments were carried out with many kinds of liquid fuels under the different initial conditions. One of the main results of this experiment is that benzene and alcohol have greater flame velocities and increase the flame velocity of petrol by blending with them. Therefore, the increase in flame velocity is one of the reasons why these mixed fuels show more resistance for knocking.
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Fujio NAGAO, Syuniti OHIGASI, Masayuki KITAO, WanBou Wah, WuHwan Dung
1951 Volume 17 Issue 62 Pages
5-9
Published: 1951
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The purpose of the present research is to determine the method of injection, injection pressure, starting period of injection and compression ratio, favourable in the manifoldinjection engine, and also to investigate the anti-knock characteristics and to compare them with those in the carburetor system. With the manifold-injection engine, the direction and the shape of the fuel spray, injection pressure, and the start of injection have not too serious effect on performance as in the cylinder injection engine. Especially, when the spray is directed against the air-flow, very low injection pressure (even 10 atm) can be applied. The start of injection of 90-120°after TDC on the suction stroke is optimum. Manifold-injection is superior to carburetion with respect to anti-knock characteristics. In the manifold-injection engine, slightly later spark is favourable than in the carburetor engine.
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Syuniti OHIGASI, Hideo KIMURA
1951 Volume 17 Issue 62 Pages
10-13
Published: 1951
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In this paper, the rate of combustion in the cylinder of the gasoline-injection engine is calculated by analyzing the indicator cards, and the relations between the rate of combustion and thermal efficiency, and the effects of the combustion progress on the performance are investigated. In the fuel-injection engine, the combustion proceeds faster at the early stage after ignition than in the carburetor engine. The nature of the cycle, therefore, resembles to that in the constant volume combustion cycle and has good thermal efficiency. The highest indicated thermal efficiency is obtained when the spark is so timed that the highest rate of combustion appears right after TDC.
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Taira TAMURA
1951 Volume 17 Issue 62 Pages
14-17
Published: 1951
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Benzine's octane number is more than 100, but they say, it is apt to knock on commercial engines. More than ten years ago, benzene was blended in gasoline, but not now. We tried to make these combustion characteristics clear, and compared the benzene, toluene, xylene and gasoline with each others, in 1944. This experiment was operated by a air-cooled single cylinder testing engine. As testing fuel ; pure benzene, toluene and xylene were mixed with 72-octane gasoline free from aromatic compound, and their octane numbers were 92. And the 72-octane gasoline containing lead-liquid was added to make its octane number 92. We obtained knocking zones, out-put courves, and other characteristics of these fuels. Then we found these aromatic compounds could be used as high class internal combustion engine fuel, especialy at low intake mixture temperature, and toluene, was the best in these aromatic fuels.
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Takeo MORITA, Naoyosi KUMAGAI
1951 Volume 17 Issue 62 Pages
17-21
Published: 1951
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Liquid water was injected into an intake pipe of a single cylinder engine through a selfcontrolling nozzle. In this procedure ; the proper amount of the additional water increased the output of the engine. This increase is greater than that of the inlet-air. This fact should be explained by isolation of the latent energy, such as vibrational one, in the molecules of the burned gas. With an addition of water, the knocking combustion was suppressed exceedingly and the combustion velosity was increased. The pressure characteristics of the knocking combustion was also investigated by oscillograph of the electromagnetic type. It was found that, in the knocking combustion, the so-called 'end gas'in the cylinder had been ignited spontaneously before the arrival of the flame front. This result affords the experimental basis with respect to the mechanism of the knocking combustion.
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Fujio NAGAO, Takasi KOBAYAKAWA, Masayuki KITAO, Isao SIMIZU
1951 Volume 17 Issue 62 Pages
21-24
Published: 1951
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The performance of a small hot-bulb engine has been studied at several fuel injection timings. In this experiment it often happened that the carbon deposit accumulated in the hot bulb, made the performance worse. Therefore, the method how to keep from this trouble has been researched. From the results of the experiments carried out with a small hot-bulb engine, it was ascertained that the carbon deposit is caused by a part of unevaporated fuel before ignition. Therefore, the optimum injection pressure and injection timing were studied to meet this requirement.
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Fujio NAGAO, Kiyoshi KITANI, Haruo TOKUNAGA, Hiroshi MURATA
1951 Volume 17 Issue 62 Pages
24-30
Published: 1951
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For the calculation of the pressure change in the cylinder and the ante chamber of a Diesel engine, hitherto numerical or graphical method has been applied. The present authors have devised an analytical approximate solution of the pressure difference between the ante chamber and the cylinder, by which the throttling loss and the compression work can be calculated. The loss of work calculated by this formula are too great to be neglected for the high speed engine practically used. Hence to remove the throttling loss for compression stroke, we contrived a new combustion chamber. From the results of the experiments carried out on the high speed Diesel engines with different kinds of ante chambers, the new combustion chamber was found to be superior to the original one with respect to fuel consumption.
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Fujio NAGAO, Takasi KOBAYAKAWA, Kinmei WAKABAYASI
1951 Volume 17 Issue 62 Pages
30-32
Published: 1951
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The brake mean effective pressure of a small hot bulb engine is very low, so that the power loss for compressing the scavenge air in the crank case and the distribution of friction loss to every part of the engine were clarified. The engine employed in the experiments was a small hot-bulb engine with bore and stroke 120mm each, developing 5〓 at 900 r.p.m. The friction loss of every part was measured by motoring, successively removing the air valve and the cylinder cover. Simultaneously, the pressure in the crank case was recorded by an oscillograph using a photo-electric tube indicator. The pumping loss measured from the pressure diagram is fairly coincident with the one obtained by motoring test. The total loss is about 37% of which the friction loss is 18%, pumping loss 9%, friction loss due to cylinder pressure 10%.
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Fujio NAGAO, Takasi KOBAYAKAWA, Tositeru TAKAOKA
1951 Volume 17 Issue 62 Pages
32-35
Published: 1951
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When the fuel with much distillation residue was used in a small hot-bulb engine, there remained a great deal of carbon deposit in the hot bulb. In order to find out the cause and the method to keep from this trouble, the process of fuel injection, combustion, and time lag of ignition were studied. From the results of experiments with a small hot-bulb engine (120mmφ×120mm, 5〓 at 900r.p.m.), two types of combustion were found out. The one occurrs in the case of earlier fuel injection, accompanied with sudden pressure rise and a great deal of carbon deposit. The other occurrs in the case of later injection with better atomizing, resulting smooth combustion and less carbon deposit.
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Naotsugu MASUGI
1951 Volume 17 Issue 62 Pages
35-41
Published: 1951
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This new CO
2-meter consists of the next four main parts, (1) forward-orifice, (2) chemical CO
2-absorber like KOH, (3) backward-nozzles, (4) vacume-pump or steam-ejector. Maintaining the backpressure of the backward-nozzle simply under the critical pressure, the quantity of gas-flow after the CO
2-absorber is normalized, and by the law of continuity of materials, the CO
2-percentage can be indicated by the manometer of the forward-orifice. According to the resut of the several experiments, this apparatus seems to be useful to the practical uses, especially to the burning test of industrial furnaces because of its simplicity and correctness.
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Naotsugu MASUGI
1951 Volume 17 Issue 62 Pages
41-46
Published: 1951
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This apparatus is a simple gas analyser, which uses the adiabatic component as parameter, and is made of several nozzles constructed in nozzle-bridge as the electric-bridge type. Sucking a flue gas through them and maintaining the back pressure of the last-nozzles under their critical pressure, the change of the pressure distribution between some nozzles can indicate the change of the components of the gas, and the CO % can be found at once. In several fundamental experiments we have suceeded in this new principe.
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Sugao SUGAWARA, Takashi SATO, Keiichi HASEGAWA
1951 Volume 17 Issue 62 Pages
47-51
Published: 1951
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This paper is the report of experiments for the combustion test of Babcock-Wilcox boiler with chain grate firing combined with pulverized coal supply. The experiments were made under various ratio of fuel supply and rate of combustion. The fuel used for fire grate is lignite and that for pulverized coal is UBE coal. The conclusion is as follows : The efficiency of combustion depends upon the rate of combustion, ratio of fuel supply and excess air factor is 80∼85%. The reasonable value of rate of combustion is about 65∼70 kg/m
2h and that of excess air factor is 1·3∼1·4. The efficiency of boiler depends upon the rate of load of combustion chamber and ratio of fuel supply and for the rate of combustion of 300, 000 kcal/m
3h, its value are about 62%, 70% and 73% for 2/1, 1/1 and 1/3 of ratio of fuel supply respectively.
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Sugao SUGAWARA, Norio HUKUI, Humiya YAMAMOTO
1951 Volume 17 Issue 62 Pages
52-56
Published: 1951
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The influence of forms of nozzle and diffuser, relative position of nozzle and diffuser, suction vacuum and delivery pressure, on the characteristics of air ejector, was experimentally researched, using compressed air of 1·2∼2·9 ata, the maximum suction vacuum and delivery pressure being 20 mmAq and 120 mmAq respectively. The conclusion is as follws : For low pressure air ejector, the parallel nozzle whose length of parallel part is about twice of its diameter, is suitable and it is desirable for diffuser that its length of parallel part is about 2·5 times of its diameter. The ratio of diameter of parallel part of diffuser to that of nozzle should be about 5. For the relative position of nozzle and diffuser, when the exit edge of nozzle coinsides with the inlet edge of diffuser, the ratio of quantity of suction air to that of used air becomes maximum and its value attains to 2·7 in the best condition.
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Hiroshi AOKI
1951 Volume 17 Issue 62 Pages
57-63
Published: 1951
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In case of small torque air turbine has often been used for the purpose to obtain high speed, for example to drive Gyro, Ultracentrifuge, and Internal-Grinder etc. In this case, usually radial flow impulse type has been adopted for its simple construction. It appears that there are few reports proposed up to this time concerning the turbine of such type with which we can conclude turbine efficiency, and so concerning Parallel nozzles used for it. An investigation was made to present a complete design data applied qualitatively to this type turbine design. The contents of this paper are as follows : (1) The characteristics of the radial flow type air impulse turbine and the best profile of buckets have been presented and checked by experiments. (2) Experiments of the radial flow type air reaction turbine have been given. (3) The author points out that bucket velocity coefficient of the turbines of this type will be about 0·6, and the comparison of the two has been discussed. (4) Results of reaction tests of parallel nozzles have been given, and he presents analytically simple formulae to conclude velocity and discharge coefficient of parallel. nozzles with arbitrary dimensions.
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Ichimatsu TANISHITA
1951 Volume 17 Issue 62 Pages
64-70
Published: 1951
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A new equation of state for air was obtained on the basis of the experimental results of Amagat and Witkowski as follows : ν=29·27 T/P+1·09059·10
-3-8·50053·10
-3r
1·64+4·25852·10
-9Pr
24·9-6·27588·10
-16p
2r
2·92+2·78867·10
-23P
3r
3·17 where P is pressure kg/m
2, T=273·16+t is absolute temperature °K, t is temperature °C, ν is specific volume m
3/kg, r=100/T. This equation is valid to 1, 000 at above 0°C, to 120 at above -35°C, to 80 at above -80°C and to 40 at above -100°C. Calculation was made of the numerical values of ν, i and s from this equation and its derived equations, and it was constructed Mollier's diagram and temperature-entropy diagram. The calculated values of specific heat at constant pressure is in accord satisfactorily with various experimenal results.
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Hideo UCHIDA
1951 Volume 17 Issue 62 Pages
70-77
Published: 1951
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In this article the new characteristic equations, tables and diagram of mercury made by the author are shown. Those equations, except that for specific volume of saturated liquid mercury, were made by the author. The equation which indicates relations between saturation pressure and temperature of mercury vapour suits to the experimental data published by Smith, Menzies and the others for 250 to 1, 000°K with small errors. The formula for specific heat of liquid mercury was obtained for -20 to 280°C, using the data by J. H. Awbery's experiments. The other characteristic equations were made by thermodynamical calculations. The author calculated the characteristic values of mercury of pressure range from 0·0010 to 60 kg/cm
2 and temperature range to 700°C and made the tables and enthalpy-entropy diagram of mercury.
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Tatuhiro UEDA
1951 Volume 17 Issue 62 Pages
78-83
Published: 1951
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On the n-mediums refrigerating cycle, it has been shown on this paper that the theoretical coefficient of performance is expressed as follows [numerical formula] In this equation, ε
1, ε
2, ……ε
n, are theoretical coefficients of performance of each medium cycle. On the n-stages refrigerating cycle, it has been shown that if we consider that each stage of this cycle is corresponding to each refrigerating cycle respectively and these coefficients of performance are also ε
1, ε
2, ……, ε
n, then the total coefficient of performance would be also theoretically expressed by the above equation. Through these considerations, the required conditions have been obtained in order to gain the maximum total coefficent of performance.
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Tomokazu ASANO, Tsuyoshi ASANUMA, Ukichi TANAKA
1951 Volume 17 Issue 62 Pages
83-87
Published: 1951
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Hitherto the direct method for obtaining pressure-stroke diagram of rockdrill has not been exsisted. We designed a new type indicator to fullfill this purpose. The motion of the piston hammer was led by a rod fixed to it to the rear part of the machine, and this motion was reduced to about 6 mm proportionally by a simple lever link mechanism and then transformed to a swing motion of a recording drum. On the other hand, both pen-levers swing horizontally according to the pressure variations in the front and rear chambers of the drill. In this way it is able to draw about 40 pressure-stroke diagrams (5×5 mm) directly on a film wound around the recording drum. Besides, the indicator carries two sets of actuating cams so as to avoid the harmful wear of the pick-up pistons and to prevent the superposition of the figure.
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Itiro WATANABE
1951 Volume 17 Issue 62 Pages
87-89
Published: 1951
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Takashi OHNO, Osamu TANIGUCHI
1951 Volume 17 Issue 62 Pages
89-95
Published: 1951
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Centrifugal field will be formed in the pipe by the spiral motion of air when the compressed air is injected through the nozzle installed tangentially on the pipe wall. If such process is carried out adiabatically, temperature gradient will be exist along the radial direction. Then temperature difference between the center and the periphery will be noticiable. Some devices will be able to sperate the injected compressed air into two parts, warm and cold. Such apparatus is called as vortex tube. We designed several constructions of vortex tube and investigated their characteristics experimentally and theoretically.
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Ryotaro IZUMI
1951 Volume 17 Issue 62 Pages
95-97
Published: 1951
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In the present paper, the author tried to experimentally determine the heat transmission coefficient of rotating circular cylinder immersed in an air stream. Using a 400 mm diameter Gottingen type wind tunnel, air velocity v varies in the range between 2 m/s and 18 m/s (R
e=vd/v=1×10
4∼6×10
4), and as for the peripherial velocity of cylinder vθ, it varied stepwise as 1·83 ; 3·07 and 5·26 m/s respectively. To avoid the end effect, the guide cylinders are installed at both ends of the main cylinder (40 mm diameter) and heated with the Ni-Cr wires (0·5 mm diameter). The surface temperature is measured with the Cu-Constantan thermo-couples. (the diameter of which being 0·15 mm). We verified, in the cases of free and forced convections, that the heat transmission coefficient α kcal/m
2-h-°C is independent of the temperature difference Δθ°C, and from these tables we constructed the tables of N
u∼R
e, N
u∼vθ/v. From these tables it is clear that the increment of Nusselt Number N
u lies in the range 2·01∼12·56 for vθ/v=0∼1·5. In conclusion, the author wishes to express his hearty thanks to prof. Dr. Y. Tanasawa for his valuable advice for this work.
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Hidekichi KATAOKA
1951 Volume 17 Issue 62 Pages
98-102
Published: 1951
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Heat conduction of a finite rod due to a given constant flow of heat is treated by F. Ollendorff in the following. Rothe-Ollendorff-Pohlhassen : "Funktionen Theorie und ihre Anwendung in der Technik". In the above discussion he assumes that flow of heat takes place only in the rod and is insulated perfectly to the opposite side of heat source. In the present paper, flow of heat takes place not only in the conducting rod, but also in surroundings through an insulator.
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Hidekichi KATAOKA
1951 Volume 17 Issue 62 Pages
102-109
Published: 1951
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Let Q (t) be the rate of flow of heat from heat source per unit contacting area per unit time. We shall discuss in this paper in previous problem the following 4 cases, Q (t)=γ sinω x(t-β), S-γ sinω (t-β), γ cosω (t-β), S-γ cosω (t-β).
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Sugao SUGAWARA, Itaru MICHIYOSHI
1951 Volume 17 Issue 62 Pages
109-114
Published: 1951
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In this paper, we studied theoretically the heat transmission by the natural convection from a vertical flat plate to the gas which is in contact with the plate. At first, we showed that coefficient of surface heat transmission analyzed by means of the energy equation for the temperature boundary layer, coincided very well with Schmidt's and Beckmann's experimental results. And then we analyzed the surface heat transmission in the case of variable temperature in the direction of x, that is in case of 1. T
1-T
0=B
xβ, and 2. T
1-T
0=A+B
x, where T
1=temperature of flat plate T
0=temperature of cold gas B,
β=constant A=constant. (≐̸0)
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Sugao SUGAWARA, Itaru MICHIYOSHI
1951 Volume 17 Issue 62 Pages
115-121
Published: 1951
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In this paper, we studied theoretically the surface heat transmission by laminar natural convection from the vertical flat plate to the gas, especially considering what differences Prandtl number of gas brings to the relation between temperature-distribution and velocity-distribution near the plate. And then we analyzed the relation between natural convection and forced convection, when both convections occur in the same direction, and found that, the natural convection is influenced severely by the other flow (for example, forced flow), and when the velocity of forced flow is comparatively small and the temperature differences between the flat plate and the gas is so large, the influence of the natural convection which effects on the forced convection can not be neglected.
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Sugao SUGAWARA, Takashi SATO, Shoichiro YOSHIMURA
1951 Volume 17 Issue 62 Pages
122-129
Published: 1951
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We wished to research systematically the relations between surface heat transfer and fundamental elements that were seemed to effect heat transfer, and we experimented on flat plate, which was considered to be able to make clear the effects of many elements comparatively easily and systematically, but has not yet been studied enoughy by experiments. We experimented in unsteady state ; that is to say, we knew the surface heat transfer coefficient by measuring the temperature difference between main flow and the surface of plate, in varying condition, during heating and cooling the plate. Also we made clear the conditions of boundary layer by measuring the velocity distribution in many cases, for instance ; for the plate having the sharp front edge, the flat front edge and the half flat front edge and also in the case of increasing the turbulence of main flow by screen.
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Sugao SUGAWARA, Takashi SATO, Atsuo KADONO, Mitsuo ANDO
1951 Volume 17 Issue 62 Pages
130-136
Published: 1951
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In the 1st report, we reported on the experimental results regarding to heat transfer at the surface of smooth flat plate in forced flow. In this report, we report on the results of experiments on rough plate. It is thought that the effect of roughness on surface heat transfer, is varied by height, depth, pitch and shape of roughness elements. At first, we experimented on the effect of the pitch of elements of roughness. Roughness of surface is given by making the parallel grooves that is perpendicular to flowing direction. In the case of flat front edge plate, the special turbulent boundary layer was seen in any position over certain Reynolds'Number, and in its range, N
u/R
e was constant in any R
e. And the value of N
u/R
e was maximum in the case of a certain pitch for grooved plate with same depth, where N
u is Nusselt's Number and R
e is Reynolds's Number.
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Sugao SUGAWARA, Takashi SATO
1951 Volume 17 Issue 62 Pages
137-142
Published: 1951
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We performed the theoretical researches, in regard to heat transfer at laminar boundary layer, in the case of the flat plate with temperature gradient on its surface that was in the forced convection, by considering the fluid was non-compressive gas. At first, we obtained the exact solution and next the approximate solutions to be able to show the out-line of influences of many elements on heat transfer plainly. In both solutions, we assume that T
1-T
0=A
xm, where T
1 and T
0 are temperatures of themain flow and that of the surface respectively, and x is the distance from the front edge of plate in the flowing direction. We calculated on the many cases by changing m values, of m and Prandtl's Numbers. And it is shown that value of the coefficient of surface hea transfer in the case of m=0.5 is 40% larger, and in the case of m=1 it is 60% larger, than that of in case of m=0.
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Tatsuo YUGE
1951 Volume 17 Issue 62 Pages
143-148
Published: 1951
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This paper has been written with a view to make clear the relation between the distribution of the heat transfer coefficients and that of the pressure in the part of the laminar boundary layer along the surface of the two dimensional Bodies of various shapes, placed in a uniform stream. We have solved the problem theoretically, considering that the physical constants comprised in the governing equations of velocity and temperature fields, are functions of temperature. And our theoretical solution was mostly in agreement with many experimental results and along with it the cause of disagreements between the experimental results was made clear.
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Kensuke KAWASHIMO, Shigebumi AOKI
1951 Volume 17 Issue 62 Pages
149-153
Published: 1951
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The heat loss of a heat insulated horizontal pipe in air is commonly determined from the hypothesis, that the heat transfer coefficient is constant overall. But, including the effect of natural convection, it is not constant, but a function of angle. In this investigation, when the coefficient of heat transfer is expressed by Fourier series of colatitude, the analytical methods of determining the temperature and heat loss distribution and the overall heat loss are obtained. We made the fundamental study of a method of heat insulation, according to which the thickness of heat insulating material should be a function of colatitude of pipe.
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Harumi ASAWO
1951 Volume 17 Issue 62 Pages
153-157
Published: 1951
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I have obtained the similarity between oil cooling-pipe and oil heating-pipe, where the oil flows in a stream-line flow and its viscosity changes by temperature only and the other physical properties are constant. As a relation of viscosity and temperature, I have applied the Vogel's equation (29). I have reduced the similarity of (32) from the foundamental equations, by dimensional analysis, where θ
m is dimensionless mean temperature of issued oil and Wc/kN is Graetz number and s'is a dimensionless groupe which are defined by (34), and t
∝ is a proper temperature of oil. As general liquids, these viscosities are not so large, always we can take -273 instead of t
∝. Then Vogel's equation becomes Andrade's equation (2) and s'becomes s (24) and similarity is (26). When change of viscosity is taken into consideration, θ
m is not only affected by Graetz number, but affected by dimensionless quantity s'.
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Naoziro YAMANAKA, Tatuhiro UEDA, Thuyoshi OHASI
1951 Volume 17 Issue 62 Pages
157-161
Published: 1951
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This report is the one of the experimental results of heat transfer on the revolving steam condenser tube, under the conditions : the contained air 0∼30% by weight, and film condensation. The experimental apparatus used is revolving condenser tube which was reported by Professor N. Yamanaka on this Journal, 1937. The results of the present experiment show that on the revolving condenser, not only the coefficients of heat transfer, but the safety for the air effect, are considerably increased.
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Takuro OKAZAKI
1951 Volume 17 Issue 62 Pages
161-163
Published: 1951
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The effect of the air contained in nearly saturated steam condensing on a vertical wall was analytically deduced from the equation of molecular and convective diffusion.
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Kiyoshi YAMAGATA, Fujio HIRANO, Kaneyasu NISHIKAWA, Hisamitu MATUOKA
1951 Volume 17 Issue 62 Pages
163-167
Published: 1951
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In order to investigate the mechanism of bubble formation in nuclear boiling, we have taken many photographs of bubbles on a horizontal heated plate by using the lens system and optical box of oscillograph, and at the same time we have measured by thermocouples the temperature of a heated flat plate and the temperature distribution from the surface of plate to the water level. The conclutions are shown as follows : (1) The type of bubbles are classified into four i.e. sphere type, bell type, couple type and tandem type. (The former two are simple bubbles and the latter two multiple bubbles) In case of distilled water, the rate of generating simple bubble decreases with increase of heat flux, and in case of city water, it is about 100% independent of heat flux. (2) The duration of adhesion of bubble to a surface is almost proportional to the cubic root of diameter of bubble leaving the heating surface.
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Harumi ASAWO, Gen ISHII
1951 Volume 17 Issue 62 Pages
167-172
Published: 1951
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We have calculated numerically temperature distribution, velocity distribution and pressure gradient of castor oil which flows in a stream-line flow inner heating-pipe of a constant temperature. The method of numerical solution is same as that of the oil cooling pipe, Rep. II. The author's method for partial differential equations is to extend the idea of Simpson's integral for ordirary differential equations, and this idea is that to approximate a small part of curve by parabola. Moreover, we have calculated mean temperature t
m°C of oil in cooling pipe and heating pipe, where mean temperature means that of mixed oil which issued from the pipe. And these author's resultants were compared with Nusselt's and Yamagata's result, assuming that the viscosity of oil is constant. For this comparison of these results, we have taken dimension-less groupe θ
m≡(t
i-t
m)/(t
i-t
w) as a mean temperature.
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Kensuke KAWASHIMO, Shigebumi AOKI
1951 Volume 17 Issue 62 Pages
173-177
Published: 1951
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In the theoretical analysis of cooling, Newton's law is commonly used, but it seems that the error is too large as temperature increases. In order to determine the deviation, we attempt to analyse by Stefan-Boltzmann's law of radiation. We can obtain the temperature distribution by an approximate method and revise the Bachmann Chart, in cases of slab, cylinder and sphere, respectively. It is recognized, from our result, that the deviation from the analysis with Newton's law becomes about 50%, when the temperature of body is over 600°C.
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Seikan ISIGAI, Koji AKAGAWA
1951 Volume 17 Issue 62 Pages
178-183
Published: 1951
Released on J-STAGE: March 28, 2008
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The heat absorption of block-covered water-walls is less than that of the ideal cases when the surface temperatures are equal to the inside water temperatures, because of the resistance to heat conduction between the water-wall surface and the inside boiler water. We investigated on the heat resistance by measuring the electric resistance of suitably constructed models and then corrected the results by the actual temperature distribution data, and thus determined a method of calculation. The coefficient showing the proportion of actual heat flow to the ideal case can easily be found by using the diagram presented in the paper. For usual bare-faced cast-iron blocks, the coefficient falls between 0·92 and 0·98, and we recommend 0·95 for approximate calculations.
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Bunji ARIMA
1951 Volume 17 Issue 62 Pages
184-188
Published: 1951
Released on J-STAGE: March 28, 2008
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The near Infra-redray was projected on a thin slice of potato, and than the dryness of the test piece was observed. Further, I studied the dry velosity and the evaporated water and the amount of contained water etc……. Drying by the Infra-redray is much bettter than other two ways, That is, the spontaneous dryness and the drying by the electric heater. An attempt was executed about the observation on the charge of temperature at the inner part of the test piece.
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Tatuhiro UEDA
1951 Volume 17 Issue 62 Pages
188-194
Published: 1951
Released on J-STAGE: March 28, 2008
JOURNAL
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With a view to improving fabric dryer, an experiment was made to determine the drying curve under various drying conditions. Two methods of drying were applied to a few fabrics. In one method, heated air, flows perpendicularly to the fabric, passes through the fabric texture, for the drying purpose and in the other the fabric comes in contact with a metallic plate heated by hot water. The drying curves are separated into two parts, periods of constant rate of drying and decreasing rate. as to the period of decreasing rate, more important in practical case, we may belive as follows by comparing the experimental results with the theoretical consideration. The distribution of moisture content on drying subject (fabric) is similar to the distribution of temperature on heat transfer. So in this paper, the relation between the period of constant rate and that of decreasing has been shown. Then we may discuss on the fabric dryer whether improvable or not.
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