Influence among nozzle guide vanes on the performance of a water-jet pump
Two crucial parameters,namely the radial height and distribution of the nozzle guide vanes,were taken into consideration,based on the initial nozzle guide vane structure.The influence of various nozzle guide vanes on the thrust and noise performance on the water-jet pump was studied by hybrid method of DES and FEM.The numerical results illustrated that as the radial height of the nozzle guide vanes decreases,the thrust and flow rate of the WJP increase while the torque de-creases a little.Besides,the guide vane passing frequency is still identified as the main frequency of internal flow noise,al-though the amplitude of sound pressure level decreases 2.43％.The overall sound pressure level of internal flow noise in-creases.When the nozzle guide vanes are distributed around the guide cone,the thrust of the water-jet pump increases by 1.03％,flow rate increases by 0.76％and toque increases a little.Meanwhile,the amplitude at the main frequency of sound pressure level decreases by 2.05％and the overall sound pressure level of internal flow noise decreases.Additionally,the main frequency of internal flow noise shifts to the impeller blade passing frequency and the guide vane passing frequency be-comes the secondary frequency.However,the difference in sound pressure level amplitude between these two frequencies is small.There is impeller blade harmonic frequency in different schemes.Internal flow noise energy is predominantly found within the low to medium frequency band.
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