Research On A Novel Electromagnetic Expansion Valve And Its Experiments

Refrigeration and air-conditioning industry has more than 100 years of history. Compressor, evaporator, condenser and expansion valve are four basic components. Expansion valve has more that 70 years of history. It has mainly experienced there stages: the initial fixed orifice, the expansion valve adjusted by manual, the thermal expansion valve and the electronic expansion valve which can be regulated automatically. Forced by the pressure of the energy crisis, energy-saving has been emphasized. The electronic expansion valve has wide adjustment range and a strong and intelligent superheat control regulation characteristics. It also has very fast response characteristic and it has achieved good mechanical and electrical integration. So it has been widely used nowadays. This paper is to design a novel electromagnetic expansion valve, which is driven by PWM pulse.This article aims to provide a systematic method to design a novel electromagnetic expansion valve, which is based on the combination of theory, experience and the combined simulation with multiple simulation software. It can be used to design the expansion valve quickly and accurately to meet the requirements of the users. The contents include: 1)theoretical calculation and FLUENT simulation are carried out to design the structure and parameters of the valve port and to check the distribution of the pressure and the flow field to meet the requirements of the flow path and flow rate of the valve; 2)theoretical calculation and the ANSYS software are used to optimize the structure and size of the electromagnetic solenoid; 3)ANSYS simulation software is applied to check the stress and deformation of the key parts of the valve(such as the valve port and the seal and so on) to ensure that the strength and performance of these parts meet the design requirements; 4)AMESim simulation software is applied to simulate the dynamic characteristics of the valve,(including the movement of the spool and the flow rate of the valve) to find out main factors to influent the dynamic performance of the valve.Based on the above ideas, the paper has designed a direct action type valve used in smaller valve port and a pilot operated valve used in larger valve port and two patents has been applied. Due to time constraints, only the smaller valve has been produced. In order to test the valve, the PWM controller supplying 24V DC voltage has been designed and produced.In this thesis, Many experiments has been carried out for the valve: such as open-loop flow rate test, leaking test, the differential pressure when the valve cannot be opened. Some test has done to put the valve into the air-conditioning system to match the system. The system performance under different duty cycles has been analyzed. After these tests, all the design requirements of the valve have been met and the controller can meet the design requirement through practical application too.