INTERNAL FLOW INVESTIGATION AND NOISE REDUCTION OF THE CROSS-FLOW FAN USING THE VARIABLE TIP CLEARANCE TONGUE

A new variable tip clearance tongue is used in the cross-flow fan of the split type room air- conditioner.Experimental results show that the fan using the new variable tip clearance tongue has a better aerodynamic performance,and has a better noise characteristic.In this paper,the fan using the new variable tip clearance tongue with the skew blades along the span,the fan using the conventional tongue with the skew blades,and the fan using the conventional tongue with the straight blades along the span are contrasted in internal flow,aerodynamic performance and noise characteristics.Internal flow characteristics simulated numerically based on three-dimensional Navier-Stokes equations coupled withκ-eTurbulence model show the movement of eccentric vortex along the span with the variable tip clearance which is different with the fan using the conventional tongue.The research discusses the mechanism that the variable tip clearance tongue affects internal flow and reduces noise of the fan.