高精度流体热物性测试实验系统的研制

Development of Fluid Thermophysical Property Measurement System with High Accuracy

在分析各种流体热物性参数测量要求的基础上,借鉴前人研究经验,结合最新的温度、压力等参数测量与控制技术,完成了流体热物性测试用的温度测量系统、高精度控温油/水槽、高精度控温酒精槽、压力测量系统、真空及配气系统、配套的测试与控制软件等的研制与开发,最终形成了一套相对完整的测试实验系统平台.在实验系统的运行范围内,最佳的温度测量不确定度小于±1mK,恒温槽15min的温度波动度可优于±1mK,压力测量的准确度为量程的0 01%.大量的实际运行结果表明:新研制的流体热物性测试实验系统性能稳定,测试结果可靠,为目前正在进行的流体热物性测试自动化研究奠定了良好的基础.

A new thermophysical property measurement system with a special purpose software is developed, which consists of a temperature measurement system (range 190-570 K, the temperature uncertainty less than ±1 mK), a pressure measurement system (range 0-13.8 MPa, the accuracy better than 0.01%), an oil thermostat bath (range ambient temperature -570 K, the temperature stability less than ±3 mK per 15 min), a water thermostat bath (range ambient temperature -360 K, the temperature stability less than ±1 mK per 15 min), two alcohol thermostat baths (range 210-320 K, the temperature stability less than ±15 mK per 15 min, range 190-230 K, the temperature stability less than ±15 mK per 15 min), a vacuum system, a mixture make-up system and etc. The software to measure the temperature and pressure, control the thermostat baths and refrigeration system is developed with the virtual instrument technology. To improve the performance of the thermostat baths, a new quasi-two-dimension Fuzzy PID control algorithm for temperature is developed. With the new experimental system, the vapor pressure, PVTx properties of fluids can be measured automatically, which provides an experimental basis for automatic measurement of thermophysical properties of fluids.