The thermal effect experiments were carried out of a direct air-cooled system in the low speed wind tunnel. The influence of effect factors on recirculation is also discussion, after that the relationship between the thermal flows field structure and recirculation ratio under the cooling tower is analyzed. At last, the engineering measures to reduce or avoid recirculation are proposed. For certain conditions the experimental measurement shows close agreement with numerical values.
Numerical investigation of large thick and low Reynolds airfoil of wind turbines by mounting indented Gurney flaps was carried out. The influenced rules of the position of Gurney flaps on the aerodynamic performance of airfoil under same height of flaps were achieved, and the optimal position of Gurney flap was presented. At last, the mechanism of wind turbine performance controlled by Gurney flap was discussed. The results can provide the theoretical guidance and technical support to wind turbines control in practical engineering.
Wheel/rail rolling noise is the main source of noise from railway operations, it is at least
as important as aerodynamic noise. In this paper, the makeup of unit modules of CAE(Computer
Aided Engineering) simulation platform for of railway passenger car and its function frame are
given. Based on finite element method, boundary element method, the structural model, interior
acoustic cavity and acoustics model of electric locomotive wheel were analyzed by Nastran and
Sysnoise software. This paper is imposed sinusoidal excitation on the wheel, and then the laying of
the viscoelastic layer and optimization of damping-wheel, obtain the wheel’s structure of the
vibration noise radiation.The analysis result shows that the laying of the viscoelastic layer can
reduce wheels radiation noise, and the noise can be reduced from 0.27 to 8.62 dB.Practical
application indicated this simulation platform can supply effective technology support for the
development of product.
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