Modeling structure of non-axisymmetric end wall of local ball impression on lower end wall of front edge of movable blade of gas turbine

Abstract

The invention discloses a modeling structure of a non-axisymmetric end wall of a local ball impression on the lower end wall of the front edge of a movable blade of a gas turbine. The modeling structure of the non-axisymmetric end wall of the local ball impression is arranged on the lower end wall of the front edge where a rotary-static disc cavity of the gas turbine is in contact with a high pressure stage movable blade of the gas turbine of a radial rim sealing structure. Non-axisymmetric end wall modeling is carried out on the lower end wall of the front edge of the movable blade by means of an end wall modeling axial control line and an end wall modeling circumferential control line. Main flow gas forms a near wall vortex in the upstream of the front edge of the movable blade by meansof the local ball impression end wall formed by the modeling structure of the non-axisymmetric end wall of the local ball impression, so that the pressure flotation in the circumferential direction ofa main flow near a sealing outlet of a rim is reduced effectively, and therefore, the invasion degree of gas is reduced, the temperature of a turbine disc is reduced, and the heat transfer stabilityof the turbine disc is improved. Meanwhile, the efficiency loss increased by end wall modeling is controlled to a very small degree by means of a relatively small sunken degree, and the influence on integral operation of the turbine is very small.

Description

technical field [0001] The invention relates to a non-axisymmetric end wall molding structure, in particular to a gas turbine with the function of reducing the intrusion of gas in the disk cavity used in the gas turbine with the rotary-static disk cavity structure and the high-pressure stage of the high-temperature steam turbine. The local spherical concave non-axisymmetric end wall shape structure of the lower end wall of the leading edge of the translation blade. Background technique [0002] In axial-flow turbomachinery such as aero-engines, heavy-duty gas turbines, supercritical and ultra-supercritical steam turbines, after high-temperature gas flows through the high-pressure stage vanes, due to the interaction between the vane wake and the leading edge of the rotor blades, the rotor and static parts High pressure and low pressure areas alternate in the circumferential direction and change constantly with the rotation of the rotor blades are formed near the gap. In the ...

AI Technical Summary

Problems solved by technology

The end wall shape of the concave wall surface will lead to a decrease in the local pressure at the leading edge of the rotor blade, reduce the main flow circumferential pressure fluctuation, and reduce the gas intrusion into the disk cavity; the end wall shape of the convex wall surface will cause the stagnation area of ​​the rotor blade leading edge to move forward, increasing the local pressure , increase the main flow circumferential pressure fluctuation, and increase the gas intrusion into the disk cavity

At the same time, the end wall shape of the leading edge of the rotor blade increases the total pressure loss of the rotor blade compared with the design of the axisymmetric end wall. The reduced gas intrusion effect and the increased efficiency loss should be considered in the design

At present, most of the structural optimizations to reduce the gas intrusion in the pan cavity are aimed at the sealing structure itself. The flow inside the seal is changed to reduce the amount of cold air required for sealing. There are few studies on changing the structure of the main flow end wall to reduce the fluctuation of the circumferential pressure of the main flow.

Images