异程布置的冷冻水系统管网水力特性计算方法

大型中央空调冷冻水系统管网水力特性精确计算是研究其优化设计和运行的必要条件，简化模型因计算误差大而无法应用于大型管网拓扑结构的水力计算。以异程布置的冷冻水系统为研究对象，在充分考虑末端支路温度调节阀调节特性的基础上，建立了管网水力特性精确数学模型，提出了虚拟流量的计算机逻辑算法。以10个AHU支路的异程式管网为仿真计算对象，计算该管网最小供回水压差以及不同供回水压差条件下的各支路温度调节阀开度和实际流量，计算结果符合异程式管网存在较大压力不平衡的固有特性。该计算方法能够确保计算收敛，实现了利用一个逻辑程序计算管网各种水力特性，为异程式管网水力特性研究提供了参考价值。

Calculation Method of Hydraulic Characteristics for Direct-Return Chilled Water System

In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence.