EXPERIMENTAL STUDY ON FRICTION COEFFICIENT AND HEAT TRANSFER CHARACTERISTICS OF ELLIPTICAL PIN FIN CHANNEL AT ROTATING STATE

In this study, an elliptical pin-fins array is proposed to enhance the heat transfer coefficient (HTC) of turbine blade trailing edge channel. The friction coefficient (f) and HTC are obtained at the condition where inlet Reynolds number (Re) ranges from 10,000 to 70,000, rotation number (Ro) ranges from 0 to 1.0, temperature ratio (TR) ranges from 0.04 to 0.22, and Buoyancy number (Bo) ranges from 0 to 2.55. The streamlined design of the elliptical pin-fins allows the fluid to enter and pass through the channel more smoothly, thereby reducing flow disturbances at the inlet and minimizing the loss of heat transfer efficiency. Under low Re conditions, the pin-fins enhances fluid mixing, making the TR a significant factor affecting HTC. Under high Res, due to the complexity of fluid flow, the influence of the TR is relatively diminished. Similarly, under rotational conditions, the Coriolis force alters fluid flow direction and velocity distribution, increasing heat transfer intensity and making the impact of the TR more pronounced. The relationship between f and TR variation is not evident. The f is relatively small at lower Ro (0.1 - 0.3), then significantly increases as the Ro reaches 0.35. Subsequently, there is a slight fluctuation with the increase in Ro, exhibiting an overall trend of first decreasing and then increasing..