转臂式离心机工作室内的瞬态温度求解与分析

考虑大型转臂式离心机圆柱形工作室各墙壁(顶板、底板和侧壁)的瞬态导热,建立各墙壁的瞬态温度控制方程,对控制方程进行Laplace变换并求解,得到了透过墙壁内表面的总热流量与工作室内空气温度的关系.同时,综合考虑离心机驱动系统输出功率与工作室内空气和固体部件吸热、墙壁系统的吸热和导热、出风口带出的热量,以及动能与进风口带入的热量和动能之差等供能与耗能之间的平衡关系,建立工作室内瞬态温度控制方程,导出了工作室内空气瞬态温度的Laplace变换像函数的解析表达式.然后,采用求解Laplace逆变换的展开定理,导出了工作室内空气瞬态温度随时间变化的级数型显式表达式.最后,以一台多用途离心机为例,进行了工作室内空气温度的理论计算,与以前只考虑墙壁稳态导热的理论计算相比,瞬态计算结果与实测结果更加接近.所建瞬态温度公式提高了工作室温度的预测精度,有助于提升大型转臂式离心机工作室温控设计的水平.

Research on Transient Temperature in the Work Room of a Rotary Arm Type Centrifuge

Firstly,in view of the transient heat conduction in the top,bottom and side walls of the work room of a rotary arm type centrifuge,the governing equations of transient temperature for the walls were developed.Through the Laplace transform and solution,the total heat flux a mount permeating the interior surfaces of the walls in terms of air temperature in the work room was obtained.Then,the governing equation of transient air temperature in the work room was established according to the energy conservation principle.In the equation,the input ener gy from the drive system was balanced with the total energy absorbed by the air and solid parts in the work room,absorbed and transferred out by the walls,and taken away by the outflow air over inflow air.Finally,the explicit series expressions of the transient temperature in the work room were deduced by means of the expansion theorem of the inverse Laplace transform.As an example,the work room transient temperature of one constructed geotechnical centrifuge was computed theoretically and the results were compared with the experimentally measured values.The comparison indicates that,the theoretical solution is in good agreement with the experimental one.The established transient temperature formula can increase the forecast accu racy for the work room temperature and improve the temperature control design of the work rooms of rotary arm type centrifuges.