The laminar free convection problem for a flat plate which is placed vertically in air is treated, taking into account the variation of properties of air which depends on temperature. Previously the author solved the same problem by perturbation theory using ε=(T₀-T₁)/T₂ as a small parameter, where T₀ and T₁ are the absolute Temperatures of the surface and the surrounding air, respectively. In this reports the regorous solution for larger value of ε(=2.0 and 4.0) by successive approach method is presented. The film coefficient can be expressed as follows : α=α_ε=0(1-0.055ε) 0<ε<4.0

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This paper shows a theoretical analysis of the heat transfer to a liquid-metal flowing turblently on a flat plate. The construction of analysis is performed on the following assumption. (1) The velocity distribution in the boundary layer on a plate comforms to a new semitheoretical formula studied by Hama recently. (2) The physical properties of a liquid-metal are constant. (3) The turbulent boundary layer is divided into the viscosity layer and turbulent layer. The shearing stress and heat flow flux in the viscosity layer equal to those values at the plate surface. The distribution of shearing stress in turbulent layer is similar to one of the heat flow flux, and the heat flux transported through the sectional element vertically to the flow direction is proportional to the velocity at that place. (4) The molecular diffusion is considered at turbulent layer.

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The writer has carried out an approximate solution on the heat transfer due to the natural convection around the horizontal elliptic cilinder and obtained a relation between Nusselt number (Nu) and Grashof number (Gr) as follows : Nu=0.604(√(1-ε²)/K)^1/4g(x)_m·Gr^1/4 in which ε is the eccentricity of the cross section of the cylinder, K a constant depending on ε, x the angle of obliquity and g (x)_m a function of x depending on ε. The numerical results are tabulated and expressed by a diagram comparing with those of horizontal and vertical flat plates or circular cylinders.

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A formula for the heat transfer of the dropwise condensation on the vertical flat surface was presented by N. Fatica and D.L. Katz. But Calculated value of the heat transfer coefficient from the formula is very lower in comparision with the experimental value, as it excepts one important factor which may increase the heat transfer by the action of the natural falling droplets, that is, these droplets act to fall forcedly many other growing droplets on the surface. In this paper, the formula included this factor was found and mainly compared with the Fatica-Katz's experimental data.

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On the assumptions that a radiating gas mass having a uniform coefficient of absorption exists in the center of the furnace and that between radiating gas mass and walls exists transparent gas, the emissivity of a gas mass radiating to furnace walls and the frequency distribution of the heat-flow intensity on furnace walls are calculated. When the volume ratio of radiating gas to furnace is about 0.2, the frequency distribution calculated coinsides closely with that of actual furnaces, which is independent of the form of furnace or operating conditions. The average absorptivity of the gas mass for the radiation between any two of the furnace walls is also presented in the present paper. The results will be able to be utilized for calculating the heat absorption in any one of the furnace walls.

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There have been more than one publications issued on the heat transfer of nucleate boiling under a pressure lower than atmospheric pressure, but little is yet known about the mechanism of boiling. The experiments given in the present work have been carried out with distilled water with the ranges of heat flux and pressure covering 9000∼30000 kcal/m²h and 0.4∼1.033 kg/cm² abs. respectively. It has been verified that the diameter of a bubble just leaving the heating surface decreases and the frequency of bubble formation increases with pressure and that the generation of bubbles becomes irregular under reduced pressure. The physical meaning of pressure factor in the correlating equation of nucleate boiling heat transfer that had been derived by one of the authors, has not been clarified yet. The data of the present experiment have led the authors to find that the pressure factor is only modifiable to the rate of growth of bubbles.

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