螺杆式风冷冷水机组动态模型的开发及验证

给出了螺杆式风冷冷水机组动态过程模型。机组的高、低压段被分成制冷剂侧、管壁、以及水或空气侧三个控制容积。针对每个控制容积建立了质量和能量平衡的微分方程。由于压缩机和热力膨胀阀具有较小的热惯性 ,因而采用稳态模型描述压缩过程和膨胀过程。膨胀阀感温包中的制冷剂温度对于蒸发器出口温度的延迟用一阶惯性环节来描述。通过“预测 -校正”和“自适应步长”方法实现了系统仿真 ,仿真结果与测试数据吻合良好。

Development and Validation of Dynamic Model about Screw Air-cooled Chiller

In this paper, a dynamic model of screw air-cooled chiller is presented. The high-pressure and low-pressure segments are divided into three control volumes as the refrigerant side, tube wall, and water or air side. Time dependent ordinary differential equations are obtained from the mass and energy balances for each control volume. As the compressor and thermostatic expansion valve (TEV) have very small thermal inertias, steady-state models are applied for the compression and throttling processes. The variation of the refrigerant temperature in the TEV's bulb to that at the evaporator outlet is described with a time dependent ordinary differential equation. System simulation is finally carried out with 'predictor-corrector' and 'adaptive integration step' methods. Simulated results are in good agreement with the measured data.