Heat exchange in the case of pulsating turbulent pipe flow of gas under resonance oscillations

The effect of heat exchange in the case of pulsating turbulent pipe flow of gas under resonance oscillations is analyzed. The hydrodynamic and thermal characteristics of a pulsating flow is different from the characteristics of a steady-state flow. It is observed that the Nusselt number in the exhaust pipe of a pulsed combustion chamber in which oscillations with large relative amplitude occur can increase more than two times as compared to the value of Nu for the steady-state flow. Thermal characteristics also depend on the Prandtl number Pr, on the distance to the place of initial heating, and on the thermal conditions at the tube wall. For a pulsating flow in a relatively long tube, whose length is comparable with the acoustic wavelength, the compressibility of the flow is menifested. The frequency dependence of the amplitude and phase of oscillations of the tangential stress at the wall attain their minimums, which causes a decrease of the relative power consumed on pumping the liquid through the tube.