热驱热声制冷耦合系统中波导管的声传输特性

Transmission characteristics of waveguides in heat driven therm-oacoustic refrigeration systems

根据声传播规律和声场边界条件分析,在热声发动机和热声制冷机之间增加一段波导管,可以有效提高制冷机回热器的驱动声压,同时增加当地声阻抗,降低回热器平均振荡速度,减少黏性耗散.波导管传输特性的计算和分析表明:波导管的特征尺寸(包括特征长度和相对水力半径)是提高回热器声压和声阻抗的关键参数;相对水力半径和阻抗相角是影响波导管最佳特征长度的主要因素,无量纲阻抗幅值的变化将会加剧这种影响.依据波导管的声传输特性,通过选择较大的面积比和降低波导管长度实现热驱热声制冷耦合系统中的阻抗匹配设计,实现热声发动机与热声制冷机的协调工作.

According to the acoustic transmission characters ot the waveguides and the boundary conimproved by adding a waveguide between the therm-oacoustie prime mover and -the refrigerator. Calculation of the transmission character shows that the characteristic sizes of the waveguide namely the characteristic length and the relative hydraulic radius are the key parameters. The mare factors affect the optimal characteristic length are the relative hydraulic radius and the impedance angle, and the change of the dimensionless impedance magfftude Will exacerbate fhis effect. Based on the sound transmission characteristics of waveguide, ,he impedance -marcia driven therm-oacoustie refrigeration system can be realized by selecting larger area ratio and smaller length.