| With the continuous development of marine turbocharger,the turbine components develop in the direction of large expansion ratio and transonic turbine,and then the intake/exhaust volute matched with it and its mutual influence gradually enter people’ s vision.Although compared with the turbine,the intake/exhaust volute will not directly affect the performance of the turbocharger,but its structure will indirectly affect the operation state of the turbine,thus affecting the overall performance.Therefore,to explore the optimization scheme to weaken the flow loss inside the inlet/exhaust volute,and to explore the flow between the inlet/exhaust volute and the turbine in the whole flow channel is another main means to improve the turbine performance.First,the flow field of the direct current intake volute is analyzed,and the internal flow field is explored,and the main loss sources are found.Under the condition of reducing the total pressure loss coefficient,the double twisted line and circular arc are adopted to optimize the structure of the volute.Compared with the prototype,the total pressure loss coefficient of the double twisted line is reduced by about 7%,and the circular arc is reduced by about 8%.The circular arc is higher uniformity coefficient,and the circular arc is simpler than the double twisted line in the structure.Subsequently,the flow field of the ‘box’ volute exhaust volute was analyzed to explore the main internal loss sources.On this basis,it was optimized without changing the maximum axial length,and the expansion ratio of the volute annular diffuser was unevenly changed.Thus,the total pressure loss coefficient of the volute was reduced,and the static pressure recovery coefficient was improved.Moreover,the volute under different swirl angles was explored.It is found that the optimization scheme can effectively weaken the vortex motion inside the volute,reduce the total pressure loss coefficient by about 17%,and improve the static pressure recovery coefficient by about 19%.Moreover,the optimized inlet static pressure coefficient is about 0.04189 smaller than that of the prototype,which improves the working ability of the turbine.At different swirl angles,the performance parameters of the exhaust volute show periodic changes.The volute has good adaptability to the change of swirl angle before the swirl angle is 15°.When the swirl angle reaches 15°,the performance of the volute is the best,and 25° is the worst.When the swirl angle reaches 40°,it can provide lower outlet back pressure for the turbine rotor blade.Finally,the prototype and optimized inlet/exhaust volute are combined with turbine blade respectively,and the single channel simulation is carried out to explore the better combination scheme.At the same time,the overall performance of the inlet/exhaust volute is studied,and the turbine blade is copied to simulate the more real flow field.The whole channel and single channel are compared to explore the interaction between the inlet/exhaust volute and the turbine.Compared with the prototype,the optimized inlet/outlet volute can increase the total static efficiency by 1.19%.In the whole channel,the total-static efficiency is0.78% lower than that in the single channel with uniform boundary.The turbine stator cascade can improve the uneven flow caused by the air flow from the intake volute,so as to provide a more uniform flow for the rotor blade,and the intake volute has a greater impact on the leading edge of the turbine stator with 10% and 50% blade height.The influence of exhaust volute on circumferential 90° and 270° blades are the most obvious,and the influence of inlet uneven static pressure distribution on rotor blade is much greater than that of turbine blade.And the circumferential inhomogeneity of the volute has the least effect on the blade at 180°position,so the blade can be placed at 180° position with single channel simulation to replace the whole channel simulation to reduce the use of time and computing resources. |
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