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22 巻, 120 号
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柴山 信三1956 年 22 巻 120 号 p. 523-524
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーPDF形式でダウンロード (458K) -
甲藤 好郎1956 年 22 巻 120 号 p. 525-529
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーAlmost problems of heat conduction can be readily treated by graphical or numerical methods, which, therefore, are important not only in engineering practice but in the other fields. But if the ambient temperature or the heat generation varies with time, it is undesirable to treat the problem by the conventional graphical or numerical methods. In such cases, we can solve the problems more easily, as Duhamel's theorem in the theory of heat conduction, by using time-temperature relations gained in the case of steady-state ambient temperature or heat generation. This paper describes the above-mentioned methods and points out certain items to which special attention should be paid in applying them.抄録全体を表示PDF形式でダウンロード (748K) -
馬渕 幾夫1956 年 22 巻 120 号 p. 530-534
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーThe exact solutions of gravitational heat convection about a heated vertical flat plate in the air have been obtaind by Pohlhausen, and recently Ostrach has found the solutions for the various Prandtl numbers by means of I.B.M. calculator. These solutions neglect the variation of property values depending on temperature except the bouoyancy term. The large temperature difference between the plate and the surrounding undisturbed air must have some effects for the heat transfer due to the variation of properties depending on temperature. Recently, Hara has obtained a solution by perturbation theory using Pohlhausen's solution as 0 th approximation, but his solution has a limit of application at the larger temperature difference due to the perturbation theory. In this paper, the author has used Squire method by which the approximate polynominals for the velocity and temperature distributions may be obtained applying momentum and energy integral equations, in order to avoid the tedious calculations. Calculated value of the local Nusselt number can be expressed approximately by next formula : [numerical formula] where Tω and T∞ denote the absolute temperatures of the flat plate and the undisturbed air, respectively and Nu∞ and Gr∞ are respectively local Nusselt and Grashof numbers evaluated at the undisturbed condition and ω is 0.76 for the air.抄録全体を表示PDF形式でダウンロード (705K) -
菅原 菅雄, 岐美 格, 南山 竜緒, 久留島 忠憲1956 年 22 巻 120 号 p. 534-539
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn this report, following the previous report, the authors have presented the heat transfer from a vertical flat plate (70×40×1cm3) by natural convection in the case where the transition from laminar to turbulent flow occured. And they clarified the effects of the disturbance by the turbulence plate (which was set near the front edge of the flat plate) on heat transfer. Arranging the data of the experiments, the authors reached the following conclusions : (1) The relation between non-dimensional numbers, Nux and Gr, in the laminar flow region becomes as follows : [numerical formula] (2) The transition to turbulent flow begins to occur from Gr=6×108 (3) By using the turbulence plate, transitional point moves forwards, and the relation between Nux and Gr, becomes as follows : [numerical formula]抄録全体を表示PDF形式でダウンロード (842K) -
菅原 菅雄, 岐美 格1956 年 22 巻 120 号 p. 540-545
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーThis paper deals with the discussion on the relation between the mechanism of dropwise condensation and three considerable factors, which are closely related to the dropwise condensation ; namely, the critical size and shape of a drop, the area covered by droplets and the sweeping cycle ; and also with experimental and theoretical analysis of each factor. According to this study, it should be considered that the heat transfer by dropwise condensation is thoroughly decided by those three factors which are severely affected by various conditions, that is : the temperature, pressure and velocity of steam ; non-condensable gas ; the size, shape and inclination of condensing wall ; the character of condensing surface ; the temperature of cooling liquid ; the cooling rate and so on.抄録全体を表示PDF形式でダウンロード (1323K) -
菅原 菅雄, 岐美 格, 南山 竜緒, 尾島 正規1956 年 22 巻 120 号 p. 546-551
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーWe experimentally investigated on the heat transfer by dropwise condensation of saturated steam on a vertical flat condensing surface (effective area was 21×6cm2) promoted by oleic acid, particularly to make clear the effects of steam pressure on the heat transfer, in a pressure range of 17.5∼1140 mmHga. The following results are obtaind : (1) When the flow rate of cooling water is constant, the heat load on the condensing surface is proportional to the square root of the steam pressure. (2) The steam-side coefficient of heat transfer is almost independent of the flow rate of cooling water, and it increases it proportion to the 1/4 power of the steam pressure. (3) The overall coefficient of heat transmission from steam to cooling water decreases by about 10%, as the steam pressure is reduced from 1 ata to 0.1 ata.抄録全体を表示PDF形式でダウンロード (841K) -
西川 兼康, 川野 通彦1956 年 22 巻 120 号 p. 551-556
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn nucleate boiling the physical meaning of liquid level above the heating surface had never been clarified. Therefore, we carried out the experiments for this purpose, and found that there was an effective stirring length of bubbles which was proper to liquid. This is the effective height from heating surface to a liquid level, through which the bubbles have the stirring effect. The effective stirring length of bubbles relates to the drag of rising bubbles. The following relation was obtained from the experiments. [numerical formula] where He=the effective stirring length of bubbles, R=the representative length of the heating surface, R^-e·b=the bubble Reynolds number, d0=the diameter of vapour bubble just leaving the heating surface, Um=mean rising velocity of bubble and υ=the kinematic viscosity of liquid.抄録全体を表示PDF形式でダウンロード (889K) -
西川 兼康1956 年 22 巻 120 号 p. 557-561
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーBy introducing the idea of the effective stirring length of bubbles, the following equation of nucleate boiling heat transfer was derived and it was shown that the equation had good agreement with the experimental results. [numerical formula] (laminar flow), [numerical formula] (turbulent flow), where [numerical formula] cp=specific heat of liquid, γ' and γ"=specific weight of liquid and vapour, λ=thermal conductivity of liquid, σ=surface tension of liquid, γ=latent heat, R=the representative length of heating surface, q=heat flux, α=coefficient of heat transfer, M=900 m-1 and P=1.699 kcal/h. The average line of many experimental results could be represented by the following correlating equation. [numerical formula].抄録全体を表示PDF形式でダウンロード (710K) -
西川 兼康1956 年 22 巻 120 号 p. 562-570
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn the previous report an equation of nucleate boiling heat transfer was proposed, but the equation can be applied only to the clean smooth heating surface. This equation must be corrected by means of foamability for the dirty or roughened surface, and the coefficient in the corrected equation plays similarly to the emissivity in the radiative heat transfer. Further, when the experimental results under a pressure higher or lower than the atmospheric pressure are correlated by this new equation, the experimental points are separated according with the magnitudes of pressure. In this case the pressure ratio needs to be taken into consideration. Lastly, the correlating equation which is applied to all cases in nucleate boiling heat transfer, becomes as follows : [numerical formula] where fζ≡ζ/ζs=foamability, fp≡p/ps=pressure ratio, ζ=coefficient of foaming ability for any combination of surface and liquid, ζs=coefficient of foaming ability for the combination of clean smooth surface and pure liquid, ps=atmospheric pressure, p=any pressure, and X and Y=number of no dimension mentioned in the previous report.抄録全体を表示PDF形式でダウンロード (1166K) -
中村 行三, 沢田 照夫, 松下 正幸, 大中 恒明, 山手 邦一, 山本 博康1956 年 22 巻 120 号 p. 570-575
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーOur new heat transmitting tubes, which are superior in point of heat transmission in the case of fluid flowing across the tubes, are the ones having one or two plane axial fins perpendicularly on the outer front surface of circular tubes. In the first report we pointed out that among new tubes there were two useful ones, according to the experiments using each tube independently. New experiments using the tubes as bundle have also showed that the new tubes as bundles have superior heat transmission characteristics and minor pressure losses, comparing with the bundle of ordinary circular tubes.抄録全体を表示PDF形式でダウンロード (833K) -
青木 成文, 川下 研介1956 年 22 巻 120 号 p. 576-582
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn order to study the heat transmission in turbulent gas flow, we analyse the differential equation of heat energy for laminar sublayer, in which the distribution of velocity is linear, and introduce the temperature profile and heat transfer coefficients. From this consideration, it becomes clear that the direction of heat flow is expressed by our nondimensional factor "Dissipation ratio" (reference to 1st and 2nd reports), and that the Nusselt numbers are respectively calculated from the heat flux through wall and the gas temperature change. The cooling effect based on pressure drop is expressed by Euler number and the inertia term in differential equation seems to be neglegibly small for our pourpose.抄録全体を表示PDF形式でダウンロード (816K) -
青木 成文, 川下 研介1956 年 22 巻 120 号 p. 583-589
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーWe research the heat transfer on the inside surface of innerpipe (copper 16.4 mm I.D.) of counter flow type double pipe heat exchanger, in which air flows at a temperature 30∼150°C, velocity 30∼150 m/s. The relation between air temperature change, heat flow through the copper wall, the effect of dissipated energy and of expansion due to pressure drop, through pipe is studied, from which the heat-transfer coefficient is expressed by Re, Mα, Euler number Eμ and our recommendable nondimensional value "dissipation ratio" Di. At the same time, the friction coefficient is measured at the relative high velocity air flow and compared with known formulas.抄録全体を表示PDF形式でダウンロード (890K) -
渡部 一郎, 渡辺 剛男, 仲田 哲郎, 中川 洋1956 年 22 巻 120 号 p. 590-595
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーAmong the factors which affect the performance characteristics of a pneumatic ejector, the effect of the distance α' from the nozzle exit section to the entrance of the parallel part of the mixing tube was experimentally dealt with in the present paper. It was found that the optimum distance α' for the highest vacuum and the highest ejector efficiency was α'=15mm, so long as the present ranges of experiments were concerned. As the inner diameter e of the parallel part of the mixing tube was selected as e=9.55mm, the optimum value above-mentioned yields to α'/e=1.57, which coincides with the results obtained previously by L.J. Kastner, J.R. Spooner for a pneumatic ejector. Besides, the present authors have measured the pressure distributions in the mixing tube, the results of which were compared with the theories by W. Tollmien and A.M. Kuethe. Further, the results of the present paper were compared with the results hitherto published for steam ejectors.抄録全体を表示PDF形式でダウンロード (752K) -
渡部 一郎, 渡辺 剛男, 安藤 亨1956 年 22 巻 120 号 p. 596-602
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーExperiments, as to the effects of the lengths of the diffuser and the parallel part of the mixing tube upon the performance characteristics of a pneumatic ejector, were conducted. The area ratio of the ejector was 2.923, while the distance α' from the nozzle exit section to the inlet of the parallel part was α'=8.5. The length of the diffuser was varied as 60.2mm, 160.2mm and 260.2mm, maintaining the divergence angle constant (8 degrees). The vacuum obtained and the ejector efficiency were found to remain unaffected by the length of the diffuser. Next, the length l of the parallel part of the mixing tube was altered as l/e=O.9, 3.4, 5.9, 8.4, 10.9 and 13.4, where e denotes the inner diameter of the parallel part (e=10mm). According to results obtained, the optimum value of the length l tends to increase as the velocities of the driving jet as well as the weight flow ratio G2/G1 become larger, where G1 and G2 denote the weight flow of the driving air and the secondary air, respectively. Further, it was found that the optimum values of l/e lie in the range l/e=8.5∼5, to find the coincidence with the experimental results by L.J. Kastner and J.R. Spooner.抄録全体を表示PDF形式でダウンロード (869K) -
小笠原 光信1956 年 22 巻 120 号 p. 603-608
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn this report, the transient temperature variation in a circular cylinder of finite length, which is heated at an end part by a high temperature liquid, is treated analytically. And an approximate solution for such mixed boundary value problem is obtained, under a few assumptions. Next, examining the result with respect to some special cases numerically, it is veriflied that the solution has a sufficient accuracy. Moreover, it is known that the flow-rate of heat through the heating-side surface can be written approximately in a form of f1(t)·f2(z), where t denotes the time and z, the height.抄録全体を表示PDF形式でダウンロード (734K) -
小笠原 光信1956 年 22 巻 120 号 p. 608-612
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーIn the previous report, an approximate formula giving the transient temperature variation in a circular cylinder of finite length, since the immersion of its lower end part to a high temperature bath, was deduced analytically. Now, its result is compared with the experiment. For this purpose, a special experimental method is used. One of its speciality is the direct observability of the shape and growth of the isothermal line in the cylinder. And the other, the isothermal lines thus obtained are free from the disturbances which will be aroused, if many thermocouple wires were inserted into the cylinder. A specimen is composed of two semicircular cylinders of glass, and one joinning plane (neutral layer) is painted in the thermo-colour. Then, a boundary between changed and unchanged colour region represents itself an isothermal line. Since the instance of immersion of the specimen into a bath, isothermal lines are observed from time to time. Comparing the group of isothermal lines thus obtained with the corresponding lines calculated, very good agreement is recognized.抄録全体を表示PDF形式でダウンロード (959K) -
喜多野 晴一1956 年 22 巻 120 号 p. 613-619
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーThe degree of vaporization of fuel oil in the suction pipe has been studied experimentally using gas oil in case of mixture heating. The experiment has been performed in a horizontal suction pipe under continuous air stream varying air-fuel ratio, air velocity, degree of heating, and throttle-opening. On condition that heat supply was constant, the following results were obtained : The rate of vaporization has been increased by larger air-fuel ratio under constant air velocity and lower air velocity under constant air-fuel ratio. In case of non-heating, the rate of vaporization was only few percent, but at the wall temperature of 200°C, the rate of vaporization was increased to about 30 percent. In narrow thro ttle-opening, a large percentage of fuel oil flowing along the pipe wall, the rate of vaporization being lowered remarkably, then heating of mixture (pipe-wall) has become more effective.抄録全体を表示PDF形式でダウンロード (895K) -
高橋 和, 下山 鉱一1956 年 22 巻 120 号 p. 620-623
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーThe concentration of CO2, CmHn, O2, CO, H2, and CH4 in gases collected through the sampling valve attached to the pre-chamber of the compression ignition engine, has been measured. The hydraulic pressure wave controls the sampling valve. The volume of gases in sampling tube is 300 cc at the atmospheric pressure and temperature which are collected at each crank angle ranging over about 1000 cycles. The running conditions are as follows, excess air factor is 1.9, specific fuel comsumption, 220 g/〓/h, power, 3.3 〓 at 500 rpm. There is a period after ignition during which CO and H2 are more than CO2, nevertheless O2 concentration is twice as much as them. These gases have not completed burning, but may jet into the main chamber. Besides, we can see the probability of water gas reaction equilibrium in the pre-chamber. In next duration CO comes to be much less than CO2.抄録全体を表示PDF形式でダウンロード (552K) -
高橋 和1956 年 22 巻 120 号 p. 624-627
発行日: 1956/08/25
公開日: 2008/03/28
ジャーナル フリーThe ignition or octane air mixture by rapid compression is 2nd stage ignition that follows the 1st stage ignition, within which the cool flame is observed, and the cool flame zone has been reported by D. Downs and R.W. Wheeler. The auther assured the existence of aldehyde in the exhaust gas, when fuel air mixture is compresed by motoring and compression ratio, cylinder head temperature or fuel air ratio are not sufficient to explode. Utilizing the solubility of aldehyde, the exthust gases were passed through the water. That solution was coloured by the reagent, and the moles of aldehyde were measured by means of photo-electric and colorimetric methods of analysis. Concentration of aldehyde measured by the above method represents well the degree of inactive combustion. Non-ignition curve in co-ordinates of aldehyde moles per cycle and fuel air ratio is convex for aldehyde co-ordinate and has a maximum point. The igniton curve has a steeper rate of increase and explodes before the max point.抄録全体を表示PDF形式でダウンロード (571K)
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