螺杆冷水机组稳态仿真

Steady-State Simulation of Screw Chillers

为预测螺杆冷水机组在大范围结构参数以及运行工况下的性能 ,提出了该类相应的稳态仿真模型 .模型由一系列部件模型组成 ,包括压缩机、经济器、膨胀阀、壳管式冷凝器以及满液式蒸发器 .结合顺序模块方法和连续替代方法实现了模型的求解 .模型预测结果与不同规格的 4台不带经济器冷水机组和 3台带经济器冷水机组的实验数据相比 ,误差在± 1 0 %以内 .通过模型验证发现 ,只有当压缩机一级内压缩容积比大于一定值时 ,机组才能获得高于其不带经济器时的

In order to predict the performance of screw liquid chillers in a wide range of configuration parameters and operating conditions, a steady-state simulation model is presented, which is suitable for non-economized and economized chillers. The model includes sub-models for key components, such as non-economized compressor, economized compressor, economizer, expansion valve, shell-and-tube condenser, and flooded evaporator. Sequential modular (SM) method and successive substitution (SS) method are combined together to carry out the simulation of the chillers. The convergence properties of this simulation technique were also analyzed. The present model can predict the performance within ±10% for large scale of cooling capacity including four non-economized chillers and three economized chillers. With the validated model, a sensitivity analysis on the economizer system is proposed. It is found that the cooling capacity of screw liquid chiller can be increased apparently by adding the economizer, but only when the volumetric ratio of the first stage internal compression is greater than a certain value. The economized screw liquid chiller can gain a higher COP than the non-economized one at the same time.