In this paper, it is first shown that the idea of the boundary layer, as in the case of the Newtonian fluid flow, may also be applicable to the non-Newtonian fluid flow at high Reynolds number in a wider sense R₆^*=(ρV^2-1/nL^1/n)/μ_psu^1/n (ρ : density, V : characteristic velocity, L : characteristic length, μ_psu : pseudo viscosity similar to the viscosity of Newtonian fluid, n : rheological constant) and the fundamental equations of motion for non-Newtonian fluid can be simplified by introducing the approximations of the boundary layer. Then, the relation between the thickness of boundary layer δ and the Reynolds number R₆^* can also be deduced as follows : δ/L=0(R₆^*-n/(n+1)) Moreover, as an example of the analytical treatment by the boundary layer approximations, the flow state in the portion of inlet length of a circular pipe is also analysed by means of variational method. Thus, the respective relations between the inlet length x_l, the Hagenbach's correction ΔH of non-Newtonian flow and the rheological constant n have been found by the author's researches.

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In the fourth report we studied the relations between valve-lift, discharge, lifting-force and angle of issuing-jet for the nine kinds of flat-seated valve, all of which discharge water freely in the air. From the experimental data thus obtained non-dimensional discharge q₀ and lifting-force p₀ are computed and expressed as functions of opening-ratio l/d₀ or diametral-ratio d/d₀, where l stands for valve-lift, d for valve-diameter and d₀ for valve-port diameter. These experimental formulae give fundamental values for discharge and lifting-force of disc valve and could be referred to as standard formulae in the research on disc valves of any kinds.

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The relation of the lifting force and lift of a circular disc valve which over the seat, is hereby analytically related. Making use of the momentum theory of fluid, the general formula of lifting force of any axially symmetrical valve which has a spontaneous profile is obtained. Then, taking viscosity into consideration, the relation of the lifting force and lift of a circular disc valve is developed. The value calculated from this formula is approximately in accordance with an experimental data obtained by Prof. Oki which has the following static characteristics : At first, in case of very small lift the lifting force of this valve is greater on account of viscosity. Next, when the lift is continually increased, it decreases suddenly to a minimum value and then turns to increase, but gradually reachs to a nearly constant valve.

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The flow in the impeller is affected by the incidence angle. The impellers used in this experiments are of three types ; two of which have constant passage height, but one is with an inducer and another is without, and the other has a constant sectional area all on the way from inlet to outlet, but without any inducer. The influence of incidence angle to the flow in impeller has been measured by the kiel probe and the yaw meter that rotate with the impeller. From this results, it has been recognized that the separation of the flow occurs at the triangle-area that is surrounded by the trailing face of blade and the shroud. The pressure distribution at blade face that has been measured in the experiments is compared with the results of the two-dimensional theory. This theory is found to be in comparatively good agreement with the experimental results, that is, the pressure at the blade face is influenced by the main flow only, and it hardly affected by the secondary flows that complicate the flow through the impeller.

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The present paper deals with some examinations on the kneading effect of thermoplastics by the screw extruder from a hydrodynamical standpoint view. Provided that the ratio between the rate of flow and drag flow K=Q/Q_d is known, the rate of shear D, its mean D^^- and the shear amount per unit length γcm, its mean γcm^^^- in the direction of the channel depth can be determined. Consequently if the distribution of K along the screw length is known, we can guess the total amount of kneading.

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The present paper describes the experimental studies about the melt extrusion of Polyvinyl chloride, which has been conducted with a 30mm dia. extruder. The experimental results have been treated with respect to the influence of the screw shape, its revolutions and the resistance of the dies upon the kneading effects of the products.

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Although heat conduction with phase change has a great field to be solved for its application not only to the study of various natural phenomena, but also to the practices, it seems that the study has not yet been sufficiently developed for the above mentioned purposes because of its difficulties. The authors, therefore, have tried to get a broad outlook in this field from a stand-point of dimensional analysis. Using dimensionless quantities derived from such an analysis, the partial differential equations of heat conduction can be changed to ordinary ones and it is shown that the general solutions obtained in this way include the exact solutions which have been solved likely by chance. Considerations of a dimensionless quantity being a ratio between the effect of latent and sensible heat, give an approximate and very convenient method to obtain a solution sufficiently exact when the value of the above-mentioned dimensionless quantity is large. This report also gives a rule to decide whether the moving velocity of an interface obtained in this way is higher or lower than that which would be given by the exact solution. The numerical analysis following E. Schmidt is also discussed briefly.

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The buoyancy affects laminar forced-convection heat transfer, when the approach velocity of forced flow over a vertical flat plate is small. When the surface temperature and pressure gradient are constant, the boundary layer momentum and energy equations have no similar-type solutions. In this paper, approximate solutions have been obtained by a method based on Karman-Pohlhausen-type approach, the results of which may be applied, for any Prandtl number range appropriate to liquid metal (0.005<P_r<0.05) and for local Grashof number range of considering as no small buoyancy effects ([numerical formula]). R_ex is the local Reynolds number.

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Experiments were carried out on the stable film saturated boiling of water and sodium oleate solution, using three kinds of nichrome wire, 0.6, 0.8 and 1.0mm in diameter and platinum wire, 0.5mm in diameter. The bubble dynamics in stable film boiling was studied. The product of bubble diameter just leaving the vapor film and the frequency of bubble formation takes constant value, if the radiation heat flux exceeds 1∼2% of total heat flux, showing nearly the same numerical value as in case of nucleate boiling, but it decreases with the drop of radiation heat flux below the above-mentioned one. In other words, the behaviors of bubble generation in film boiling present varied aspects according to the difference of emissivity of heating surface, even if the total heat fluxes remain the same. Though the results from the experimental values of heat transfer coefficient show fairly good agreement with Banchero's equation, the experimental points are somewhat lower than Banchero's equation below the heat flux in which the product of bubble diameter and frequency of bubble formation becomes constant. It will be, therefore, necessary to introduce a correlating equation, taking the vapor film stirring effect of generating bubbles into consideration.

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Steam ejectors have several kinds of performance characteristics according to the outside conditions of ejectors-steam pressure at nozzle inlet, back pressure of diffuser and flow rate of entrained fluid. By the experimental studies on the flow state in ejectors, the following have been concluded. (1) The performance characteristics of ejector can be classified to basic three types-high vacuum, middle vacuum and low vacuum characteristics, or which the states at diffuser throat inlet are supersonic fulfilled flow, supersonic unfulfilled flow and subsonic flow, respective1y. (2) On the high vacuum characteristics, the pressure at mixing chamber takes the lowest value independently of the back pressure of diffuser, though the pressure is a variable of the back pressure in case of the middle vacuum and low vacuum characteristics. (3) Using the rectangular coordinates with respect to the back pressure of diffuser and the pressure at nozzle inlet, the existing ranges of these characteristics are divided by the straight lines through the point-the back pressure=0 and the pressure at nozzle inlet=0 abs. (4) On the high vacuum characteristics, the pressure at mixing chamber, the pressure at diffuser throat inlet and the highest back pressure of diffuser abtainable are respectively expressed by straight lines through the point-these pressures are 0 and the pressure at nozzle inlet is also 0 abs.-against the pressure at nozzle inlet. (5) The middle vacuum characteristics can not exist when the exit area of nozzle is made too large. The high vacuum characteristics disappear when the distance between nozzle and diffuser is increased.

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The author has found a new theoretical way of calculating the emissivity of a gas which contains particles. The emissivity of a gas, which contains a group of particles, is calculated by the following equations. ε_Ga is the emissivity of the same gas when it does not contain particles. [numerical formula] where L is the thickness of gas layer. The particles are assumed to distribute uniformly and constitute spheres of equal diameter. A_P is the area of the sphere surface. Side planes of an imaginary cube, which corresponds to a sphere, are perfectly black and A_B is the area of a cube surface. As ΔL is the length of edge of a cube, A_B is 6(ΔL)². (K_GΔLΔL) and (K_GLL) are factors corresponding to the thickness of gas layers ΔL and L for ε_Ga of a gas as in above equations. There are given by Hottel and others for non-luminous gases. The experiments by the author show that the results agree well with his theoretical analysis. The experimental results by Sherman, being analysed by author's method, show no contradiction. The experimental formula by Lindmark and Wohlenberg are expressed as special cases of author's theory. For a gas, which contains two or more groups of particles calculation can be made by repeating the above method. From the calculation it is revealed that an emissivity of a gas, which contains a group of particles, is greater than that of a gas alone. In this case the temperature of particles is assumed to be not lower than that of a gas. The increment of emissivity is expressed by the above equations.

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Internal gas diffusion equations considering the internal reaction rate of porous carbon particles are introduced. Solving these equations, the formulae of the combustion rate of carbon particles are obtained. For large particles the combustion rate may be calculated from the superficial reaction rate concerning the external surface, but the combustion rate of small particles, which can be used in the pulverized coal firing, must be calculated from the above formulae. The facts that the specific combustion rate of the pulverized coal is almost independent of particle size and considerably increased with the increasing of temperature, are explained by the formulae.

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The thermal capacity of steam evaporator is the most important parameter for dynamics of control system. It is given by the form of time constant T_B and expressed by a nomograph. [numerical formula] Where w_m (weight of steel parts), w' (weight of water part), w" (weight of steam part), c_m (specific heat of steel), p₁ (steam pressure), θ₁ (steam temperature), i' (enthalpy of saturated water), i" (enthalpy of saturated steam), v' (specific volume of saturated water), v" (specific volume of saturated steam), b (total inner volume), A (thermal equivalent of work), q (heat transmitted per unit time), suffix 0 (values at standard state). The effects of changes of feed water temperature, feed water flow and load steam flow are also given by nomographs.

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Heat transfer from a piston must be large on the lower part of the liner below the bottom dead centre of the piston, since the temperature difference increases towards the lower part and moreover the piston speed becomes very low. From the view point of piston cooling, it will be more effective to cool sufficiently the lower part of the liner. To verify this expectation, experiments were carried out on a two-cycle engine, in which the temperatures of the piston and the liner were measured, chainging the cooling method of the liner. By comparing the heat transfer coefficients and the heat distributions, the following facts were found. (1) Heat transferred from the piston to the liner is largest near the top ring, when the piston is at the bottom dead centre. (2) In the case of poor cooling of the lower part of the liner, the piston temperature becomes high, especially at the piston skirt. (3) In the case of sufficient cooling of the lower part of the liner, the heat load of the top ring is partly distributed to the lower rings.

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Bending rigidity of a crankcase of high speed internal combustion engines is usually smaller in the horizontal-transverse direction of the engine, because of its common hanger-bearing-type construction. For this reason, the elastic vibration appears mainly in the horizontal direction. In our research the bending deflection of a crankcase was measured under such conditions that the load was applied to the middle point of a crankcase in the horizontal-transverse direction being simply supported at the both end-bearing centres. In analysing the results of bending tests with several models of crankcase, the calculating equations for the bending deflection of a crankcase were induced from "Torsion Theory of Thin Sections" with some modifications. The results of bending tests on regular engines show that those equations are practically adequate to calculate the deflection of a crankcase.

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In this report, the construction and the performances of the vacuum-driven transonic wind-tunnel at the Government Mechanical Laboratory were described and some experimental results obtained were also shown. The test section of the wind-tunnel has rectangular cross section and its height and breadth are 20cm and 25cm respectively. When the partly open walls with adequate opening ratios are used as the top and bottom walls of the test section, uniform and steady flow can be obtained in it for over 30 sec. in the Mach number range 0.6∼1.3. Some supersonic nozzles designed for Mach numbers 1.3, 1.4, 1.56, 1.7, 1.86, and 2.0 are installed also. In the transonic region, the force measurements of the spheres with various diameters and of the tapered wing with NACA 65A 006 section were performed. And the positions of detached shock waves ahead of spheres were observed. The static pressure distribution over the surface of double wedge airfoil with thickness ratio of 10% were measured also. These experimental results were compared with the reliable data obtained by other authors and their agreements seemed to be good.

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