Effects of vibrational relaxation of multiatomic molecules on stagnation heat transfer
Abstract
The flow and temperature fields of multiatomic gas near the stagnation of cylinder are theoretically studied, taking molecular vibrational relaxation into account, and putting importance on heat transfer performances. Based on the continuum equations, the velocity and temperature jumps of translational, rotational and vibrational degrees are considered as the boundary conditions and effects of the vibrational relaxation for subsonic flow are discussed. The total heat transferred to the surface is the sum of heats due to the translationalrotational temperature and the vibrational temperature. The ratio of the heats depends much on the ratio of the flow characteristic time to the relaxation time of molecule, and consequently the total heat is much influenced by this ratio of the characteristic times. The effect of the flowrelaxation time on heat transfer is more remarkable in the vibrational nonequilibrium than in the thermal equilibrium main flow. Even in a continuum flow of Knudsen number of about 10 to the 4, the effect of vibrational relaxation on stagnation heat transfer is still appreciable.
 Publication:

International Journal of Heat and Mass Transfer
 Pub Date:
 December 1980
 Bibcode:
 1980IJHMT..23.1625M
 Keywords:

 Heat Transfer;
 Molecular Relaxation;
 Polyatomic Gases;
 Stagnation Flow;
 Subsonic Flow;
 Temperature Distribution;
 Flow Distribution;
 Nonequilibrium Flow;
 Rankine Cycle;
 Relaxation Time;
 Reynolds Number;
 Vibrational Spectra;
 Fluid Mechanics and Heat Transfer