Features of heat transfer at increase of temperature of the working body, intensive up to 12000 K/s

Abstract

In work results of pilot studies of heat transfer are given in a cylindrical pipe which represents imitating model of a spherical pipe. Experiments are executed on a gasdynamic pipe of the opened type. The starting mode, at operation of gas-turbine engines (GTE), is one of the main modes in which sometimes there are refusals. The non-staff mode of heat transfer when thermal parameters of a gas stream exceed values of settlement can be the cause of refusal, there is an intensive local heating of a streamline surface of a structural element(s) of the engine. Pilot studies were conducted at various values of intensity of increase of temperature of a working body that has allowed to record the phenomenon of a laminarization of the thermal turbulent boundary layer (TBL) at the thermal stream directed from a gas stream to a wall of the channel. At emergence of the phenomenon of a laminarization of value of local coefficients heat transfer decrease by 2,5 – 3 times. Since opening of this phenomenon it was also shown in various situations at acceleration of a gas stream and even at high extents of heating of a wall of a cylindrical pipe at the stationary modes of a current. In the non-stationary mode and the specified direction of a thermal stream this phenomenon is revealed for the first time. As the parameter of a laminarization of TBL the temperature pressure or a temperature factor is offered, and border of area of a laminarization of TBL is size ΔT ⩾ 700 K.