CALCULATION OF FLOW CHARACTERISTICS IN HEAT TURBOMACHINERY TURBINE STAGE WITH DIFFERENT THREE DIMENSIONAL SHAPE OF THE STATOR BLADE WITH ANSYS CFX SOFTWARE
Main purpose of the presented work was the investigation of influence of three dimensional blades over flow characteristics. The paper presents comparison between experimental and CFD (Computational Fluid Dynamics) data so called verification test, impulse turbine stage with Frozen Rotor and Transient Rotor Interface modeling. Static pressure distribution was measured at mid span of the blade. The paper discusses secondary flow phenomena.
Numerical Study of the Secondary Flow in Steam Turbine Static Cascade under Varying Conditions
Based on finite element volume method and fully implicit multi-grid coupling algorithm, with a certain distortion degree of the static cascade flow field is solved in three-dimensional steady-state under subcritical, critical and supercritical flow state. The paper analyses and calculates the developmental characteristics of the secondary flow in the lower wall of the cascade channels and the aerodynamic characteristic of the cascade. The calculated results under different critical state show that the secondary flow loss of cascade end wall is bound up with cascade profile and the upper and lower endwall. Especially in the supercritical flow state, there are strong disturbances of steam flow in the cascade ends and cascade shape surface. Meanwhile, the calculated results reveal the characteristic of vortices evolution in cascade channels and also shows that the strength of secondary flow develops rapidly. Two obvious vortex areas form at the nearby of the cascade back-arc of the upper and lower endwall. The development of vortices under subcritical flow state is similar to the development of vortices under critical flow state. The passage vortex moves backward under supercritical flow state. Vortex phenomenon caused by steam flow is separated from side wall near outlet of cascade back-arc. And steam flow deflects at the same time.
THE PERFORMANCE OF STEADY DETONATION ENGINES
Propulsion systems driven by steady normal detonations are studied. The practical di‐culties associated with stabilizing a detonation wave are highlighted. The requirement on the freestream total enthalpy is considered in parallel with efiects such as condensation or auto-ignition of the fuel-air mixture and limitations associated with fuel sensitivity to detonation. A criterion for detonation stabilization is formulated and applied to an analytical treatment of a detonation ramjet and a detonation turbojet, which are the respective analogs of the ramjet and the turbojet using detonative combustion. The performance of these engines is evaluated and compared to the ideal ramjet and turbojet models for hydrogen and JP10. A limitation is placed on the maximum total temperature allowed in the combustor, based on material considerations. The results show that steady detonation engines have a small thrust-producing range, due to the requirements for detonation stabilization. Their performance is always lower than that of the conventional ramjet and turbojet because of the total pressure loss across the detonation.