热力膨胀阀容量测试系统的研制

发布时间：2018-02-02 02:18

本文关键词： 热力膨胀阀开度测试流量测试容量测试模糊自适应　出处：《中国计量学院》2014年硕士论文　论文类型：学位论文

【摘要】：热力膨胀阀作为制冷系统的重要组成部分，根据过热度变化自动调节进入蒸发器的制冷剂流量。容量是热力膨胀阀的重要性能指标，表征了热力膨胀阀的制冷能力。容量测试必须在特定的工况下进行，国家标准对其作了严格的规定。然而，目前热力膨胀阀容量测试系统在工况控制上普遍采用传统的单输入单输出控制算法，这往往忽略了工况参数之间的耦合性。因此，无法使测试工况达到理想的控制品质，从而导致容量测试精度低下。基于上述情况，本文开发了一种基于多变量模糊自适应算法的热力膨胀阀容量测试系统，实现了测试工况的优化控制和容量的准确测试。主要研究内容如下：（1）热力膨胀阀容量测试系统整机方案设计。包括开度测试装置的设计、制冷剂流量测试装置的设计和控制模块的设计。开度测试装置由传感器、电磁阀、电控比例阀、恒温槽等部件组成，实现开度-感温包温度特性曲线的测定。制冷剂流量测试装置由制冷回路、冷却水回路和冷冻水回路组成，实现制冷剂质量流量-开度特性曲线的测定。控制模块以工控机为核心，利用多功能数据采集卡实现信号采集与控制。在系统软件设计上，，利用Visual Basic6.0开发了一套可视化的测试软件，提供了友好的、易操作的用户界面。（2）制冷剂流量测试工况控制算法的研究。在分析工况参数的影响因素及参数间耦合关系的基础上，将参数自调整的多变量模糊控制算法应用于工况的控制，并对控制器的控制品质进行了分析。控制结果表明，该算法具有良好的跟踪性、较高的控制精度。（3）实验研究。对热力膨胀阀容量测试系统的实验数据进行了分析，并根据实验数据对该系统进行了性能评定。实验结果表明，该系统的容量测试相对误差在1.5%以内，容量测量合成标准不确定度为0.059kW，扩展不确定度为0.118kW，满足了课题的设计要求。
[Abstract]:Thermal expansion valve, as an important part of refrigeration system, automatically adjusts the refrigerant flow into evaporator according to the change of superheat. Capacity is an important performance index of thermal expansion valve. The refrigeration capacity of thermal expansion valve is characterized. The capacity test must be carried out under specific working conditions, which is strictly regulated by the national standard. At present, the traditional single input and single output control algorithm is widely used in the capacity measurement system of thermal expansion valve, which often ignores the coupling between the operating parameters. It can not make the test condition achieve the ideal control quality, which leads to the low accuracy of capacity testing. Based on the above situation, this paper develops a thermal expansion valve capacity test system based on multivariable fuzzy adaptive algorithm. The optimal control of the test condition and the accurate measurement of the capacity are realized. The main research contents are as follows: 1) the design of the whole system for measuring the capacity of the thermal expansion valve, including the design of the opening test device, the design of the refrigerant flow test device and the design of the control module. The opening test device is composed of sensors and solenoid valves. Electronic control proportional valve, constant temperature tank and other components to achieve the open-temperature package temperature characteristic curve measurement. Refrigerant flow test device consists of refrigeration circuit, cooling water loop and chilled water loop. The measurement of refrigerant mass flow-opening characteristic curve is realized. The control module takes industrial control computer as the core and uses multi-function data acquisition card to realize signal acquisition and control. In the system software design. A set of visual testing software is developed by using Visual Basic6.0, which provides a friendly and easy user interface. 2) study on the control algorithm of refrigerant flow test condition. Based on the analysis of the influence factors of the operating conditions parameters and the coupling relationship between the parameters. The multivariable fuzzy control algorithm with self-adjusting parameters is applied to the control of working conditions and the control quality of the controller is analyzed. The control results show that the algorithm has good tracking performance and high control accuracy. The experimental data of the thermal expansion valve capacity test system are analyzed, and the performance of the system is evaluated according to the experimental data. The experimental results show that. The relative error of capacity measurement is less than 1.5%, the uncertainty of capacity measurement synthesis standard is 0.059kW, and the extended uncertainty is 0.118kW, which meets the design requirements of the project.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP274;TB657

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