Transactions of the Japan Society of Mechanical Engineers
Online ISSN : 2185-9485
Print ISSN : 0029-0270
ISSN-L : 0029-0270
Volume 25, Issue 160
Displaying 1-19 of 19 articles from this issue
  • Satoshi NAKAJIMA
    1959 Volume 25 Issue 160 Pages 1249-1251
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
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  • Tosio KURABAYASI
    1959 Volume 25 Issue 160 Pages 1252-1258
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    The degree of atomization of a liquid jet issuing from a rotating nozzle is improved by centrifugal force and air forces laterally acting on it. This method, therefore, may be applicable not only to the oil burner in a gas-turbine or a boiler furnace, but also to various atomizing devices in chemical industry. In this paper, mechanisms of atomization were analysed by using the strobo-flush-photography. Fig. 3 shows the most typical forms of jets with the speed of rotation gradually increased : (a) is dripping, (b)∼(d) are smooth jets, (e) and (f) are wavy jets, (h) and (i) are partially sprayed jets and (k) is spray. Although these types are, at a glance, like those ejected from a fixed nozzle, many differences can be found in close observation. For instance, Fig. 4 shows the generation of uniform drops from a tip of the regularly waved jet and Fig. 8 shows the longitudinal disruption of a liquid column into two parts between which a very thin film is formed.
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  • Tosio KURABAYASI
    1959 Volume 25 Issue 160 Pages 1259-1265
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    In this paper, the effects of such factors as the speed of rotation n (rpm), discharge velocity v0 (m/s), diameter of the nozzle Dn (mm), and rotating diameter of the nozzle Dr (cm) on droplet sizes were examined with water giving consideration to the mechanisms of atomization described in the preveous report. The results may be summarized as : (1) As Figs. 7∼11 represent, the Sauter mean diameters d^- do not decrease smoothly as the value of v is increased, but form five distinct stages, where v is a resultant velocity of v0 and a peripheral velocity of the nozzle. The first stage marked by 1 in these Figs. corresponds to the mode of dripping, the second stage marked by 2 corresponds to the smooth jet, the third stage marked by 3 to the wavy jet, the forth marked by 4 to the partially strayed jet and the fifth marked by 5 to the spray. (2) Mean diameter d^- (μ) is expressed by the formulae [numerical formula] for the region of wavy jet (stage 3), [numerical formula] for the region of spray (stage 5). (3) The maximum diameter dmax shows nearly the same tendency as d^- (Fig. 15) and has the following relation : [numerical formula]
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  • Tosio KURABAYASI
    1959 Volume 25 Issue 160 Pages 1266-1273
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    This paper deals with the contraction of liquid jets under the actions of acceleration and surface tension force. At the beginning, the thickness of a jet discharged from a fixed nozzle is discussed, then with the results thus obtained for a guide, the formula for a jet from a rotating nozzle is derived : [numerical formula] where vn=discharge velocity, l=distance on the jet from the nozzle, D=thickness of the jet at the point of distance l, Dn=diameter of the nozzle, [numerical formula] (called Weber number, γ=specific weight of a liquid and σ=surface tension) and α=acceleration variable with l, but when l is small α becomes nearly equal to a centrifugal acceleration Rω2. All of the physical properties of a liquid are included in We as shown above, and when We exceeds the approximate value of 4, the effects of those properties on the thickness of a jet becomes negligibly small and the formula can be simplified as [numerical formula] The thickness of a jet discharged from a fixed nozzle can easily be obtained from these formulae, only replacing α with the acceleration of gravity g. All these formulae agree very well with the experimental results.
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  • Masao TAGA
    1959 Volume 25 Issue 160 Pages 1274-1281
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    There are many measuring methods of thermal conductivity of materials, all of which, however, are the methods conducted in stationary state. In this report, we revolved a wire ring at a certain velocity, heating it by a stationary spot heat source, and measured the thermal conductivity of the material by the relation between the measurement value of periodical temperature distribution and that of the theoretical equation, which is analyzed as a problem resulting from the heat source moving along the ring circumference. An advantage of this method is that during measurement the coefficient of heat transfered from the surface of a material can be easily kept constant. Moreover, the availability of this method was ascertained by the experimental results on some materials.
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  • Katsuhisa MURAKAWA
    1959 Volume 25 Issue 160 Pages 1282-1289
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    In the industrial heat-exchangers, there are many cases of unsteady heat transfer 10 entry length with temperature distributions of pipe-walls along the direction of axis and pressure-drop from the inlet to the outlet, and in the LMFR atomic reactors, the heat is generated from the inside or the fluid. Therefore, in these cases, the research or unsteady neat transfer which generates heat from the inside of the fluid is necessary. In this paper, theoretical solutions of unsteady heat transfer in entry length of vertical double pipes are derived. In these solution, such cases of unsteady heat transfer in entry length of vertical double pipes are tried that heat generates from the inside of the fluid, free convection and laminar flow coexist at the same time, pressure drops from the inlet to the outlet, and temperature distributions of pipe-walls vary in the direction of pipe-axis. In the solutions, the finite Hankel transform, the finite Fourier transform, the Laplace transform and Bessel functions are used. But, there is no experiment on such a case. Theoretical solutions are reduced to the steady heat transfer and compared with experiment at results.
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  • Kazuma URAKAWA, Kaneyasu NISHIKAWA, Fujio HIRANO
    1959 Volume 25 Issue 160 Pages 1290-1295
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    When water is heated in a beaker from room temperature, the temperature of the water goes up gradually and reaches the boiling point, where it becomes independent of time. The coefficient of heat transfer, however, varies with time, and after a certain lapse of time, it reaches a stationary state. This paper gives the results of experiment made under reduced pressures on the transient boiling phenomena taking place between the moment when the temperature reaches the boiling point and that when the coefficient of heat transfer becomes stationary. The experiments have been carried out with distilled water over the pressures ranging 0.2∼1.03 ata. Here is shown that the time variation of boiling heat transfer is very regular, which is caused by desorption of gas absorbed during the exposure of the heating surface to the atmosphere and that the rate of time variation of heat transfer becomes lower with pressure.
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  • Tatsu OGURI
    1959 Volume 25 Issue 160 Pages 1296-1305
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    This investigation is concerned with the rates of heat transfer from the working gases to the combustion chamber walls of the internal combustion engines. The test engine used is the four stroke spark-ignition engine with the water cooled single cylinder, bore×stroke being 114.3×140 mm. On the basis of my experimental results, it was ascertained that the coefficients of heat transfer in this engine agreed well with those which were calculated by Eichelberg's formula [numerical formula] in the expansion stroke, but did not so well in the compression stroke. Dimensional analysis has been rarely applied to the problems of periodic heat transfer in the internal combustion engines, but recently Karl Elser developed this research. In this report, improving Elser's method, the relation between the dimensionless groups was found as follows, [numerical formula]where Δs : entropy change cp : specific heat under constant pressure change θ : crank angle
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  • Tatsu OGURI
    1959 Volume 25 Issue 160 Pages 1305-1314
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    There exist a great many theoretical researches on the periodic heat transmission in the internal combustion engines. Many of them discuss the problem only from the point of view of heat conduction in the solid wall, but there are few reports on the theory of heat conduction in the working gases. H. Pfriem and K. Elser have derived the energy equation of the gases especially in the boundary layer near the cylinder wall and solved it. But they have calculated only the heat transferred from the gas space to the wall under the condition that there were not any heat sources in the gases and the adibatic compression and expansion were repeated. It is the object of the present paper to introduce the term of heat quantity in the energy equation by applying the conception of the polytropic change. By this means we can calculate the heat flow from the gases to the combustion chamber wall, when the gas cycle is quite similar to the spark-ignition engine. In the latter part of the present report, the numerical calculation is achieved, and the calculated results are compared with my experimental results.
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  • Fujio NAGAO, Harutoshi KAKIMOTO, Masaru HIRUKAWA
    1959 Volume 25 Issue 160 Pages 1315-1324
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In order to investigate the effect of the timing of swirl creation upon the combustion process of a Diesel engine, various amounts of fuel were injected from two sets of fuel-injection equipments into the main and auxiliary chambers respectively at a different period. A swirl was created in the main chamber by a violent outflow of gas from the auxiliary chamber. Swirl creation prior to fuel injection into a main chamber brings a little improvement on the combustion state, but is accompanied by an unfavorably rapid rise of high pressure. Swirl creation after ignition is more effective to shorten the after-burning of fuel, as ascertained by the high-speed photography. When fuel is injected into an auxiliary chamber after TDC, the noiseless and smokeless combustion with fairly low maximum pressure is materialized without the increase in fuel consumption.
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  • Fujio NAGAO, Harutoshi KAKIMOTO, Yoshikazu MATSUOKA, Yoshikazu FUJINO
    1959 Volume 25 Issue 160 Pages 1324-1333
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The state of air-swirl, mixture formation and combustion in the swirl chamber of a Diesel engine was studied through a glass window by using the high-speed photograthy. The air in a swirl chamber rotates in the same direction throughout the combustion. After ignition, gas flows out into a cylinder from its periphery, layer by layer. The boundary of fuel spray is blown off and the core is bent by the strong swirl. However, the distribution of fuel in a swirl chamber is mainly settled by the direction of fuel injection : 1) The fuel injected against the swirl is concentrated near the center of the chamber and remains there throughout the combustion, thereby causing soot formation. 2) In the case of fuel injection along the swirl, rich mixture forms in the peripheral layer, flows out rapidly into a cylinder and mixes there with air, thus burning up completely.
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  • Shoichi FURUHAMA
    1959 Volume 25 Issue 160 Pages 1334-1340
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    A small type Diesel engine is driven by a motor with the various μU/W value, then steam of the water is added to the inlet air, and exhaust gases of the other combustion engine is sucked in. The weight loss of the piston-rings is measured, and the following results have been obtained. (1) When the oil film is thinner than a certain extent and at the same time, the combustion products attack on it, the wear is increased greatly, however, if one of these causes is eliminated, the wear becomes very small. (2) When the exhaust gases, of which the fuel has high sulfur content, are sucked in, and the cooling water temperature is low, the engine is corroded very violently by the condensed water, containing the sulfuric acid.
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  • Shoichi FURUHAMA
    1959 Volume 25 Issue 160 Pages 1340-1346
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
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    A small type Diesel engine is operated with the fuel containing various sulphur compounds and under various engine conditions. These tests show (1) the top-ring wear is large owing to the fact that it is surrounded with the combustion products, so when gastightness of the top-ring is inadequate, the 2nd-ring wears in the same order, (2) the more sulphur is contained in the fuel and the lower the temperature of cooling water goes down, the more corrosive wear increases. The cylinder surface is corrorded by the condensed liquids of the engine exhaust gas, containing much SO3 the liquid easily penetrates into the lubricating oil, and attacks the metal surface. Chemical analysis shows that the SO3 presents itself so much in the exhaust gas, as the ratio SO3/SO2 is about 10%.
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  • Shiro NUKIYAMA, Toshiro TAKEYAMA, Shigemori OTANI, Takenori NAKANISHI
    1959 Volume 25 Issue 160 Pages 1347-1351
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The efficiency characteristics of a steam boiler are explained by an efficiency-load-excess air factor surface. We have called this surface the characteristic surface of a boiler. And we are able to draw a maximum efficiency curve to each constant fuel consumption lines on the surface. By the figure of maximum efficiency curve projected on the efficiency-excess air factor plane, the characteristic surface can be classified into two types, which we call A-type and B-type. A-type shows an indispensable condition in boiler. A steam boiler will be A-type or B-type, depending on whether sufficient air which has nothing to do with combustion leaks into combustion chamber or not. By a A-type steam boiler the excess air factor for the condition of the highest boiler efficiency increases with the increase of fuel consumption, and by a B-type boiler, on the contrary, the excess air factor decreases with the increase of fuel consumption.
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  • Shiro NUKIYAMA, Toshiro TAKEYAMA, Tokuo CHIBA
    1959 Volume 25 Issue 160 Pages 1352-1355
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The lower the boiler pressure is, the larger the temperature difference between water tube and combustion gas becomes. Hence, the boiler proper absorbs larger heat energy in low pressure operation than that in high pressure operation. At the same time the quantity of heat transferred to economizer or air preheater decrease, because the outlet gas temperature at boiler proper becomes low. But boiler efficiency increase. Though we use same fuel in the boiler, the characteristic surface of a boiler is changed by the boiler pressure. In this paper, we study the relation between boiler pressure and efficiency.
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  • Shiro NUKIYAMA, Yukio YOSHIZAWA, Shigemori OTANI, Takenori NAKANISHI
    1959 Volume 25 Issue 160 Pages 1356-1358
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    We can easily imagine that we cannot operate a steam boiler with extremely thick or thine coal layer on chain grate stoker. Even though we operate the boiler with the same fuel consumption and the same quantity of air required for combustion, boiler efficiency is not same. That is, the characteristic surface of the boiler is affected by the thickness of coal layer. In this paper, we analyse a problem of coal layer and point out the economical thickness of coal layer judging from the results of our boiler test.
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  • Shiro NUKIYAMA, Toshiro TAKEYAMA, Tokuo CHIBA
    1959 Volume 25 Issue 160 Pages 1358-1361
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In recent year, it has become an important problem that we shall have to use the coal of lower heating value in our boiler. But, we cannot find sufficient reports of this problem. So we have to have certain experiments burning good and bad coals one after another in the same boiler, and make comparative study of two characteristic surfaces. Our boiler test has revealed that the characteristic surface of a boiler is considerably affected by the heating value of coal. In this paper, we study this problem from two standpoints, the quality of coal and the construction of furnace.
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  • Shiro NUKIYAMA, Yukio YOSHIZAWA, Toshiro TAKEYAMA, Shigemori OTANI
    1959 Volume 25 Issue 160 Pages 1361-1365
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    When two or several fuels, such as the combined firing of the chain grate stoker and the pulverized coal, or the gaseous fuels and the pulverized coal, are burning in a combustion chamber, the boiler efficiency is affected by the mixing ratio of fuels, even though the total quantity of heat of these fuels are equal. Because, each fuel has its own combustion characteristics. In this paper, we analyse the characteristic surface of the combined combustion boiler with regard to the mixing ratio of fuels.
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  • Shiro NUKIYAMA, Kyozo SATO, Gizo OUCHI
    1959 Volume 25 Issue 160 Pages 1366-1368
    Published: December 25, 1959
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    Usually, we operate hand firing steam boiler in the state of damper opening constant, and stoke at certain interval. And then, excess air factor is changed between certain consecutive stokings. On the contrary, on most chain grate stoker boiler, for each fuel consumption, excess air factor, which give a maximum efficiency curve are decided. For the hand firing boiler, excess air factor has been changed, therefore, efficiency is apt to decrease comparing with one of the chain grate stoker boiler. In this paper, an experiment conducted for the purpose of finding out to what extent the stoking interval affect the efficiency, has been described. And we give a proper stoking interval, the quantity of coal for each stoking, and excess air factor in the state of maximum efficiency.
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