ИСТИНА

“Energy separation” is the re-distribution of the total energy (temperature) in a fluid without external work or heat [1]. In the present study a gas-dynamic method of energy separation proposed in [2] is investigated. It is known, if the Prandtl number of the gas not equals to unity, the higher is the flow velocity the bigger is the difference between stagnation and adiabatic wall temperature. Hence, two flows with equal initial stagnation temperature but different velocities separated with heat-conducting wall can take part in heat exchange process. In the present study compressed air with the stagnation parameters To and Po is separated into two flows. One of them enters supersonic annular channel (Mach number 2.66), which consists of profiled nozzle and conical tube. Another enters subsonic channel – cylindrical tube coaxially placed inside the supersonic channel. Three types of the cylindrical tubes are used. The first is heat insulated, the second is made from heatconducting material (copper) and the third consists of two parts: impermeable heatinsulated and permeable part. Following results are obtained. If tube is heat insulated, the average stagnation temperature at the exit of the tube T1 is nearly equal to To. In case of the copper tube - T1 < To, so the gas dynamic method of energy separation is realized. And in case of the partially permeable tube - T1 > To. Hence when the third type of tubes is used, the direction of the heat flow is reversed. The authors propose following explanation of the last results. It is measured that flow velocity and static pressure at the exit of the permeable tube are higher than at the same section of the annular channel, so gas is injected from inner channel to outer one through permeable wall. Using energy equation in the integral form it may be shown that in such case total temperature of the inner flow will be increased. Also gas dynamic method of the energy separation is investigated more particularly in a long conical supersonic channel with outer subsonic channel. Rise of the total temperature of the supersonic flow and reduction of the total temperature of the subsonic flow with various ratio of mass flow are fixed. 1. B. Han, R.J. Goldstein, H.G. Choi, Energy separation in shear layers. IJHMT, 45 (2002) 47–55. 2. A. I. Leont’ev, Gas-dynamic method of energy separation of gas flows. High Temperature, 35(1) (1997) 155-157.