Previous studies show that the tip clearance loss limits the improvement of pumpjet propulsor (PJP) performance,and the tip clearance flow field is the most complicated part of PJP flow.In this work,the non-cavitation...Previous studies show that the tip clearance loss limits the improvement of pumpjet propulsor (PJP) performance,and the tip clearance flow field is the most complicated part of PJP flow.In this work,the non-cavitation and cavitation hydrodynamic performances of PJP with a tip clearance size of 1 mm are obtained by using the detached-eddy simulation (DES).At constant oncoming velocity,cavitation first occurs on the duct and then disappears with the decrease of the advance ratio.The rotor blade cavitation occurs at the low advance ratio and comprises tip clearance cavitation,tip leakage cavitation,and blade sheet cavitation.In the rotor region,the typical vortices include tip separation vortex,tip leakage vortex,trailing edge shedding vortex,and blade root horseshoe vortex.Combined with the pressure distribution,both the Q and λ2 criteria give reliable results of vortex identification.The cavitation causes an expansion of tip leakage vortex in the circumferential direction and decreases the intensities of tip separation vortex in the whole tip clearance area and tip leakage vortex in the cavitation area,and enhances the strength of tip leakage vortex in the downstream non-cavitation area.展开更多
基金the National Natural Science Foundation of China(Nos.51709229 and 51879220)the Natural Science Basic Research Plan in Shaanxi Province(No.2018JQ5092)the Fundamental Research Funds for the Central Universities of China(No.3102019HHZY030019)。
文摘Previous studies show that the tip clearance loss limits the improvement of pumpjet propulsor (PJP) performance,and the tip clearance flow field is the most complicated part of PJP flow.In this work,the non-cavitation and cavitation hydrodynamic performances of PJP with a tip clearance size of 1 mm are obtained by using the detached-eddy simulation (DES).At constant oncoming velocity,cavitation first occurs on the duct and then disappears with the decrease of the advance ratio.The rotor blade cavitation occurs at the low advance ratio and comprises tip clearance cavitation,tip leakage cavitation,and blade sheet cavitation.In the rotor region,the typical vortices include tip separation vortex,tip leakage vortex,trailing edge shedding vortex,and blade root horseshoe vortex.Combined with the pressure distribution,both the Q and λ2 criteria give reliable results of vortex identification.The cavitation causes an expansion of tip leakage vortex in the circumferential direction and decreases the intensities of tip separation vortex in the whole tip clearance area and tip leakage vortex in the cavitation area,and enhances the strength of tip leakage vortex in the downstream non-cavitation area.
