| Abstract: | The calculation of the heat exchange and fractional resistance during the turbulent flow of a gas with variable physical properties represents a complicated problem, which can be solved only with the help of a computer (see [1, 2], for example). Fundamentally new devices, the working substance of which is a gas heated to high temperatures, have been undergoing intensive development recently in engineering. The velocity and enthalpy profiles at the entrances of such devices can be nonuniform, not coinciding with the profiles typical of developed turbulent flow; the channel walls can consist of strongly cooled metal sections and weakly cooled ceramic sections; the ceramic materials used may be rough. The enumerated properties additionally complicate the calculation of the flow of a gas with variable physical properties. In the present report we consider two cases: the flow of air heated to high temperatures in a channel with a constant wall temperature under the conditions of strong cooling, and the flow in a pipe consisting of a strongly cooled metal section and a weakly cooled ceramic section. The results are obtained numerically using an implicit finite-difference scheme. They are in satisfactory agreement with the available experimental data.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 162–166, March–April, 1978.In conclusion, the author thanks A. N. Sekundov, I. P. Smirnova, and A. B. Lebedev for useful advice on questions connected with the development of the calculation program and A. B. Vatazhin for constant attention to the work. |
