Abstract
A series of studies about heat transfer and multiflame structure in a conserved counterflow system is included in this dissertation. Heat transfer between two opposed, non-isothermal jets under counter-rotation and co-rotation is investigated, respectively. For the case of counter-rotation, effects of Reynolds number, jet angular speed (Rossby number) and Prandtl number on the efficiency of heat transfer are systematically analyzed. For convenience of physical presentations, a dimensionless heat flux (efficiency of heat transfer) is defined. The efficiency of heat transfer from the high-temperature to low-temperature swirling jet increases with the Rossby number, but decreases with the Prandtl number. The efficiencies of heat transfer are great for small Reynolds numbers when the jet angular speeds are below certain critical values, otherwise the converse behaviors hold.For the co-rotation case, the efficiencies of heat transfer between two jets under various system conditions (the same mass fluxes, linear momentum, or angular momentum) are discussed. The rotating and the axial velocities of high-temperature jets may not be the same as those of low-temperature jets in these cases. The problem in the limit of zero rotating speed on one side is also included. In this limit, a critical rotating speed at which the efficiency of heat transfer is a minimum value is found. A comparison of the efficiencies of heat transfer among typical cases is made.Additionally, the effects of Lewis numbers on the burning of multiflame structures in a conserved counterflow system are investigated numerically. The sequence of burning configurations for a stoichiometric or lean flame transition depends greatly on the Lewis number. The system with the highest temperature is a function of the Lewis number during a process of flame transition. However, the system with a maximum total burning rate is independent of the Lewis number. A difference between the system with a maximum total burning rate and the system with a highest temperature increases with the deviation of the Lewis number from unity.