Numerical Study Of Influence Mechanism Of Groove Structure And Surface Roughness On Turbulent Boundary Layer

With energy crisis growing seriously, great attention has been paid to turbulent flow drag reduction technique all over the world. As a passive control method, groove surface turbulent drag reduction technique has shown a great application prospect among the numerous drag reduction techniques, for its simple, easy and significant drag reduction effect. This paper takes research on drag reduction mechanism and characteristics of groove surface, as well as its effect on blade aerodynamic performance by numerical simulation. Also, the influence of blade surface roughness is studied for its non-negligible influence on turbulent boundary layer around the blade.For two typical groove surfaces of V-groove and trapezoid-groove, the turbulent flow field around groove plate is calculated with fluid dynamics software Fluent. By changing inlet flow rate of the computational domain, the maximum drag reduction rate and its dimensionless size of the two groove surface can be obtained. On the basis of numerical calculation results, the drag reduction performance between two groove surface are compared. Flow characteristics and drag reduction mechanism are analyzed from wall shear stress distribution, flow field characteristics near wall region and boundary layer flow parameters.On the basis of the simulation about groove plate, the trapezoid groove which has a better drag reduction effect, is applied on the surface of compressor blade rotor37, and its effect on blade aerodynamic performance is studied. Through analyzing the dimensionless size of the groove on blade surface, the proper size and distribution range of trapezoid groove are determined, and the blade model with trapezoid groove is established. Then, the feasibility of applying the groove on blade surface to reduce the flow loss is verified with numerical calculation. The pressure coefficient, friction coefficient, total pressure loss at exit of the blade with trapezoid groove are also analyzed.Besides, the finite element model of single rotor37blade is established, and the effect of surface roughness distribution on blade performance is studied based on standard k-s turbulence model and wall functions method. For the convenience of the research, the blade surface is divided into front, middle and back regions, and one of them is assumed to be rough. The influence rules of the roughness at different region are explored from the aspects of isentropic efficiency, total pressure ratio, shock wave location and wake loss. The analysis results show that the roughness in front region affects the blade performance most, arising significant flow loss, the roughness in middle region affects less, and the roughness in back reaion affects least.