Vertical axis wind generators had received wide attention for its excellent aerodynamics characteristic and other advantages. In order to study the force exerted on airfoil when it rotated a full circle, it was necessary to simulate the flowfields of airfoil within the whole range of angles of attack. In this paper, different turbulence models and C type grid were firstly employed to simulate the flow field of NACA0012 airfoil when Ma was 0.15, Re was 0.5×10 6 and the angles of attack were 10° and 70°. The results were compared with experimental data to determine the most suitable turbulence model. Then with the chosen turbulence model, flowfields of airfoil at angles of attack from 0° and 180° were simulated using three grid types. The results indicated that the results of S-A turbulence model had the best agreement with the experimental data; The boundary layer was full attached for angle of attack of 10°, while large-scale separation and vortex shedding occurred for 70°; The predicted lift coefficient, drag coefficient and driving force of C type grid agreed well with the experimental results; The net driving force would cause airfoil to rotate in the direction of the leading edge of the airfoil and it could be used to optimize airfoils.
To solve the poor precision and low efficiency of manual grinding de-weight dynamic balance of turbopump rotor, the laser de-weight dynamic balance technology of rotating machines is adopted. Combined with the advantages of laser de-weight, such as, fast processing speed high machining precision and good machined surface quality, the smooth transition of the machined surface was realized by means of hierarchical machining. According to the characteristics of the turbopump rotor structure, the equivalent transformation model for laser de-weight turbopump rotor was built to convert the unbalance into laser processing parameters, which achieve the rapid and accurate de-weight of turbopump rotor. It focuses on solving the repeatedly loading and low accuracy of manual grinding dynamic balance. To verify the effectiveness of the proposed technique, laser de-weight experiments were carried out on two turbopump rotor test pieces. A dynamic balance test bench was set up to measure the rotor residual unbalance at 1800 r/min test speed, which is low dynamic balance. The results show that the machined surface transition was smooth, the residual unbalance was small and the machining efficiency was high. The effect of laser de-weight dynamic balance reached the expectation. It is an universal technology which is not limited to the dynamic balance of turbopump rotor, but also applicable to other rotating machinery..
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.