Fluid-structure interaction analysis on flow field and vibration characteristics of gas proportional valve

Gas proportional valve (GPV) is used as the gas regulator for fully premixed low nitrogen condensing boiler, with the pressure regulation and flow output capacity determined by the condition of the valve core. To investigate the reliability of GPV valve core in engineering applications, this paper establishes three-dimensional models of the flow and solid fields, employing a coupled calculation method known as the two-way fluid-structure interaction method to analyze the characteristics of the flow field and the stability of the valve core. The results indicate that with the valve core opening, the vortex structures gradually form on both sides of the upper diaphragm, and the vibration strength of the valve core gradually increases with the formations of the vortices. The valve core vibrates the most strongly in the outflow direction, and the upper diaphragm oscillates between −0.05 mm and 0.03 mm. When the valve core is first opened to its maximum height, there will be a 0.2 mm impact rebound, and then gradually stabilize at the maximum opening position of 8 mm. Maximum stress always occurs at the stem to diaphragms connections, especially in the initial opening stage, where the stress reaching 5.17 MPa but remaining within the allowable limit of 30 MPa. This study also compares the flow field excitation with the valve core's natural frequency, identifying potential valve core resonance. This work provides valuable guidance for the flow field characteristics and valve core safety prediction of pneumatic GPVs.