Experimental And Numerical Study On Profile Loss Of Ultra Supercritical Unit

The development of high-power ultra supercritical turbo generator sets is an important measure for the power industry to achieve the goal of “energy saving and emission reduction”.Adopting the advanced design method of large enthalpy drop blade to reduce blade loss is one of the key factors to reduce the series of flow passage and improve the efficiency of the unit.In this paper,the plane cascade experimental test of different blade height in stator and rotor was carried out.The aerodynamic parameters of the cascade were obtained.The numerical simulation method was used to study the profile loss based on Reynolds number effect and the aerodynamic performance of the three dimension cascade.First,a low speed wind tunnel test rig was used to conduct the blowing experiment of the plane cascades.The experimental results include the static pressure coefficient distribution,blade loss and deviation angle under different incidence angles.Through the static pressure coefficient curve,it is known that each profile is aft-loadeding profile.The experimental results show that the loss coefficient of each cascade is in a reasonable range,and the incidence characteristics of profiles in stator blade change more smoothly,which illustrates the aft-loading profiles and the fish head type leading edge in stator blade can effectively reduce the loss and increase the stability under the condition of variable incidence angle to some extent.Based on the measured results obtained from the planar cascades experiment,the aerodynamic performance of three dimensional cascade is further studied by numerical simulation.In this paper,the SST turbulence model is used to calculate the three dimensional cascade of rotor blades,and the results are compared with the results of plane cascade experiments.The distribution of static pressure coefficient,the variation of blade loss under differnet incidence angle,and the distribution of deviation angle along blade height are obtained.Distribution of total pressure loss coefficient in the cross section behind the cascade shows that the development of channel vortices is suppressed.The position of the vortex system is close to the upper and lower end walls,which has little effect on the mainstream in the middle.The loss varies with the incidence angle curve shows the results of total loss are in reasonable range under various conditions.The total loss increases progressively under the positive incidence angle,while the lowest point exists in the negative incidence angle.From the obtained curves,it can be seen that the corresponding incidence angle is between-3 and-4 degrees.By analyzing the vorticity distribution diagram of the cross section behind the cascade,the uneven distribution along the height of blades is the result of the interaction of two opposite vortices.Because of the limitation of experimental conditions,the law of profile loss under the condition of variable Reynolds number cannot be obtained by experiments.Therefore,based on the experimental results,the aerodynamic performance of each profile under variable Reynolds number is studied by numerical simulation.The obtained curve of loss coefficient varies with Reynolds number agrees well with the experimental results under similar conditions in the literature.And by comparison,it is found that the curve is consistent with the AMDC model and Sanders model in most Reynolds numbers.Then,the curve can be used to calculate losses under actual conditions.It is also found that under the condition of variable Reynolds number,the maximum Maher number position of the suction surface and the diffusivity of the profile vary correspondingly.