Numerical Simulation And Structural Parameter Optimization Of Cross-flow Fan For Air-conditioning

The cross flow fan is a fluid mechanical device widely used in household wall-mounted air conditioner indoor units.Its structure is exquisite,the air is uniform,and the air output can be adjusted by the axial length.However,the unique eccentric vortex structure of the internal flow field makes the cross flow fan very sensitive to changes in structural parameters,and all aspects of performance are easily affected.Large air volume and relatively low noise are common goals pursued by people.Based on the Fluent computational fluid dynamics software,this paper uses RNG k-ε and SAS turbulence models to numerically simulate a certain cross-flow fan and change its structural parameters to explore the changes in flow rate,internal flow field,efficiency,and noise,and improve its integration performance.This paper first establishes a two-dimensional numerical model of the cross flow fan,uses the RNG turbulence model to calculate the flow rate and compares the experimental value to verify the feasibility of the model,and then uses the SAS turbulence model to calculate the two-dimensional flow field and aerodynamic noise,and then separately study the impeller size The main research contents are as follows:1)First draw the geometric model of the cross flow fan,then use ICEM software to divide the grid,compare the simulated values under different grid numbers to verify the grid independence,and then compare the simulated and experimental values to verify the feasibility of the model;The internal flow field cloud diagram,speed and pressure curve,radiation noise value and noise spectrum diagram of the two-dimensional cross flow fan,analyze the internal flow field and eccentric vortex characteristics and aerodynamic noise characteristics of the cross flow fan at different speeds;2)By changing the size of the impeller,five sets of numerical models with different impeller outer diameters were established for the cross flow fan,and the RNG k-ε double equation and SAS equation were used to simulate and calculate each working condition.The results showed that when the impeller outer diameter is The overall performance of the fan is best at 96mm;3)Changed the inlet angle of the fan,that is,the position of the volute tongue,compared their outlet flow and performance parameters at high speeds,and performed internal flow field characteristics analysis;combined with FW-H to solve the equation,it is predicted that each working condition is at the same set point The noise values and spectrograms of different sound sources;when the intake angle is 175°,the flow rate,efficiency and noise of the fan perform well;4)Different shapes and numbers of baffles are added to the cross flow fan.From the perspective of the uniformity of the air,the best shape of the baffles is determined to be arc;in order to reduce noise,the number is 2-3.