On the basis of the LES and Lighthill acoustic analogy theory

the computational fluid dynamics software Fluent and acoustic simulation software ACTRAN are applied to study the flow noise characteristics inside and outside the enterprise's valve

under conditions with the same flow rate but different opening degrees(100%

70% and 40%). The result shows that

when the valve's internal pressure is in low frequency

the spectrum characteristics of the same group are similar and the sound pressure amplitude is larger

which is very different from that in high frequency. When the valve opening is decreased

the turbulent intensity

fluid velocity and pressure fluctuation increases

leading to an enhancement in the whole d B SPL inside and outside thevalve

so the noise energy inside the valve becomes strong. The noise of the valve has dipole characteristics.