With the use of the integrated momentum and energy equations, an approximate calculation was carried out for the flow and heat transfer in the laminar and turbulent free-convection boundary layer on a vertical flat plate. The velocity profiles employed for laminar layer are of a polinomial of the fifth order and an exponential function of y, which satisfy the following boundary condition in addition to the usual ones : [numerical formula] The calculated results agree practically well, over the entire range of P_r, with the Ostrach's. The method of attack for turbulent flow is similar in principle to that of Eckert and Jackson, though some different profiles are used for temperature and velocity fields. When the turbulent region coexists with the laminar region near the leading edge, the average Nusselt number was proved to be [numerical formula] where G_rc is the critical Grashof number, at which the transition from laminar to turbulent occurs.

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With the use of integrated momentum and energy equations for the boundary layer, a calculation was carried out for the heat transfer to the laminar free-convection flow on a vertical flat plate submerged in a fluid with vertically ununiform temperature. The average heat transfer coefficients applicable to the cases of free convection in the fluid of uniform temperature was shown to be applied also to the present case, provided that the fluid temperature at (0.2 to 0.3)×(plate height) from the bottom end was taken as the effective fluid temperature. This conclusion was fairly ascertained by experiments.

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In this report, following the previous report, the authors have experimentally investigated the heat transfer for the parallel upward flow of the mixtures of air and water in a vertical pipe. The results may be summarized as follows : (1) The coefficients of heat transfer by Verschoor and Stermerding are comparatively suitable for those obtained from this experiments. (2) The effects of dryness fraction upon the coefficient of the heat transfer have been made clear. (3) The empirical formula of heat transfer are shown and the applicable ranges are also discribed.

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This paper deals with the thermo-aerodynamical analysis of one-dimensional steady flow in a combustion chamber for gas turbine or jet engine. The phenomena, which were taken into account in this report, include : (1) area change, (2) wall friction, (3) external heat exchange and (4) chemical reaction (combustion). The distribution of heat release by combustion, dq_c/dx, is assumed as follows : (i) dq_c/dx=200H_u(G_f/G)xe^-100x2 ( ii ) dq_c/dx=30H_u(G_f/G)e^-30x where q_c : heat release by combustion per unit mass of flow, kcal/kg x : coordinate (in the direction of flow), m H_u : heat of combustion of fuel, kcal/kg G_f/G : fuel-air ratio (weight) and dq_c/dx≅0 at x=0.3m. The following results were obtained : Though the temperature, velocity and pressure-distribution in the direction of flow are different in the both cases of dq_c/dx until x=0.3 m where the combustion ends, but those which are obtained by completion of combustion have almost no concern with the type of dq_c/dx. The increases of temperature and velocity and also the decrease of pressure are linearly proportional to the fuel-air ratio in the case of constant area of duct. The pressure drop of convergent flow is larger than those of divergent flow and constant area flow.

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We have used rectangular CO-ordinates that enable us to indicate the completness of destructive combustion. The ordinate y designates oxygen consumed and the abscissa X, (Ψ-0.5)(CO)+Ψ(CO₂)-0.5 (H₂) in % respectively. Ψ can be any real number, but Kennzahl des Brennstoffes σ₀ or unit is-useful. When Ψ equals σ₀, the perfect combustion gases are plotted on the straight line y=(tanα)X and tanα is unit. But the combustion. gases of the partial light elements of the fuel have tanα and in this case tanα is not unit, but it is to a relation 1<tanα<∞, while tanα of the heavy elements is in a relation 1>tanα>0. The more a destructive combution is incomplete, the more tanα of the light elements increases and on the other hand that of heavy compornents decreses. By this way we can compare the combustion degrees in the pre-combustion chamber with the turbulent chamber and the direct injection chamber. In the pre-combution chamber the contents of CO and H₂ are more than that of CO₂, but in the other typtcal chamber only 1ittle quantities of CO and H₂ are found.

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Authors tried experimented on flow patterns, loss of head, distribution of quantity, especially in a cross-branch section by flowing air-water mixtures into a horizontal branch pipe of 23.4 mm. in dia. They carried out the investigation from the following tow view points : -(1) ξb₁, loss of energy on account of branch only. (2)ξb₂, loss of energy including the effect of the irregularity of the stream after a branch section. In consequence, it was possible for them to make the characteristics of the loss of energy comparatively clear. Then they discovered that the coefficient of loss of head ξb₂' approximately proportionate to the ratio of energy at the main flow and the branch flow.

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In the previous paper, the present authors developed a method of estimating the performance of turbocharged Diesel engines in equilibrium operating conditions, in which the simultaneous equations existing among operating variables were graphically solved. By applying the same method, the characteristics dimensions of turbocharged two-cycle Diesel engine are calculated on the basis of given values of six operating variables at design point, i.e., excess air ratio, delivery ratio, total efficiency of turbocharger, scavenging air temperature, piston speed and brake mean effective pressure. Further, effects of these values on the performance are found out.

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In pressure-charging two-cycle Diesel engines with constant pressure, self-sustained operation of the turbocharger cannot be achieved owing to the insufficient efficiency of the turbocharger, in which case some aid must be furnished to the turbocharger. One form of aiding the turbo-charger is to attach the positive displacement blower or compressor to the engine. In this paper, by applying the method or evaluation to the performance of the turbocharged two-cycle Diesel engine presented in the previous paper, the capacities of the auxiliary blower in-series are calculated to be necessary for the given operating conditions at full load and for the stable operation at idle running. Further, the effects of the blower capacity on the performance of a given engine are found out by the same process. The results of calculation are favourably comparable with those of experiment on the practical engine.

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For the improvement of the performance of a turbocharged Diesel engine with a pulse system, the utilization of the blow-down energy is most important. The present authors have carried out the experiments on the transmission of the blow-down energy with the air model similar to the exhaust system of an actual engine. By measuring the kinetic energy of the air ejected from the equivalent nozzle at the pipe end, several factors-pipe length, pipe diameter, area ratio of the nozzle to the pipe, and exhaust pressure -affecting the energy transmission, were found out. Further the theoretical calculations were performed by means of the characteristic method. The results thus obtained argee almost exactly with those of the experiments, when the friction loss in the exhaust pipe is taken into consideration.

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A study of the idling-knock in a Diesel engine of a pre-combustion chamber type was carried out by means of accurate indicator diagrams and measurement of its body-noise. The results obtained may be summerized as follows : (1) The combustion of the fuel which has been blown out in incompletely mixed state from the pre-combustion chamber, brings about an excessively high rate of pressure rise in the main combustion chamber, which is considered as the cause of knocking noise. (2) All the method to prevent the incompletely mixed fuel spray from escaping into the main chamber, for instance, a small burner passage, a large pre-combustion chamber, wide spray angle, large distance from injection nozzle to the passage, etc, are effective for reduction of the knock in idle running. However, these methods are not always suitable for the best performance under heavy load. (3) "Pintaux" nozzle is effective to eliminate the idling-knock without sacrificing the performance under heavy load.

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At a certain crank angle just after opening or just before closing of poppet valves (suction or exhaust) in the internal combustion engine, there is practically little suction or exhaust-action, so that such a crank angle is termed an ineffective angle and the corresponding valve lift is called an ineffective lift. To examine the effects of engine speed and pressure difference between suction and exhaust sides on the ineffective angle or lift, we carried out some experiments by an air-cooled single-cylinder four-stroke engine. Certain results obtained are summarized as follows : a) Regardless of engine speed and pressure difference, the minimum value of the ineffective angle remains constant at about 13°∼15° i.e. the ineffective valve lift is equal to about 32/100 mm in our experiments. b) The ineffective lift increases in proportion to the engine speed. c) On the other hand, the lift decreases with increasing of the pressure difference, particularly it contracts to the value of 32/100 mm at the pressure difference above 500 mm Aq.

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Ordinary, we research the characteristics of turbine blades with cascade tunnel, but we cannot expect from those researches the characteristics of turbine blades at moving state. Then, it is necessary to carry actual turbine testings to know the dynamical characteristics of turbine blades. We are researching the dynamical characteristics of various turbine blades with two testing turbines ; the one is the impulse turbine of partial admission and the other is the specially designed low pressure turbine of double motion type. In this paper, we report the results which have been obtained by the former. We measured the torque and thrust of turbine shaft, and calculated the amount and direction of exit velocity from blades. On the other hand, we measured the outlet flow angle and velocity by yaw meter and pitot tube. Then, compared these two methods and found that the first method is more simple than the second and there is good agreement between the both results.

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Though the flow modes of two-phase fluid are important in many problems such as the heat transfer and the pressure drop, there are few studies on those of upwardflow in a vertical tube. This paper mainly deals with the following experimental works : (1) Constitution diagram of flow mode regions. (2) Mechanism of transition from bubble flow to seperated flow. As the results of experiment it has become clear that the constitution diagram based on the flow rates of air and water is influenced by the diameter of pipe. Then the author proposes the new diagram which has no connection with the diameter. The above mechanism has been made clear as the stability problem of bubble motions.

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