In contemporary gearpump design

setting up unloadinggroove to ease trapped oil phenomenon is the common way.The changes of trapped oil area play a decisive role in unloadinggroove design.The calculation formula of the trapped oil area is deduced based on pressure angle of two gears as variable.Combine with CAXA

the value of trapped oil area is calculated.Virtual measuringgearpump trapped oil area is carried outby Pro/E5.0 and the reliability of the calculation formula is verified by contrastof calculated values and measured values.Based on the calculation formula of the trapped oil area

the positionwhere bidentate trapped oil area is the minimum is found.This position is traditional unloading groove opening position.At the same time

a new scheme of opening unloading groove is put forward.Only open unloading groove in the side of discharge cavity cooperatingwith gear tooth unloading decompression tank.It opens in the critical location of single and double teeth mesh.We can find the location by CAXA.Verify the feasibility of the scheme through gear pump flow field simulation based on FLUENT12.