With the development of air conditioning technology,new throttle valves such as electronic expansion valves,shut-off throttle valves and short tube throttle valves are used in air conditioners instead of capillary tubes.However,little research has been done on the shut-off throttle valve,so the flow fields of the shut-off throttle valve were calculated at different flow rates.The distributions of pressure field,velocity field,and sound power level under different operating conditions were obtained by numerical calculations.The results show that:with the increase of valve inlet flow,the maximum flow velocity at the valve throttle increases from 44.331 3 m/s to 77.560 4 m/s;with the increase of valve inlet flow,the pressure drop at the throttle also increases gradually;when the valve inlet flow increases from 0.014 kg/s to 0.024 kg/s,the maximum noise of the valve increases from 104.640 2 dB to 122.751 5 dB;the noise in the flow field is mainly concentrated at the downstream of the valve and the throttle orifice,and the maximum noise appears at the end of the straight pipe section downstream of the valve,the distribution characteristics of noise also provide direction for further optimization of valves.