Internal Flow Analysis And Experimental Study On Floor Standing Air-conditioner

Energy-efficient, low-noise and environment-friendly is always the target of airconditioner industry.Traditional fan design mainly depends on experimental method whosecost is relatively high and development life is long..Numerical study of three-dimensionalflow field of the duct system of the floor standing air-conditioner was carried out in thispaper. On the basis of detailed analysis of Velocity Field、pressure field and trace line,.The optimum designs for passage shape, the structure of bell mouth used in the multi-bladecentrifugal fan and the structure of impeller used in the multi-blade centrifugal fan werecarried out. The research aim is recalculating air volume of the standing air-conditioner andreducing the noise level of indoor unit.The optimum designs for passage shape is mainly about the modification of the exportof diffusions, so the non-uniformity of the velocity field is improved. Line type somemodification on line type of the export of diffusion was made. The width of the left side isincreased by47mm,the left angle is increased by6degrees and the right angle is increasedby7degrees, uniformity of the exit velocity is much improved.manufacture templates of airduct were made and an array of experimental investigations were carried on about airvolume flow、noise level and condensation according to national and corporation standards.Result of experiment shows that air volume flow can reach to1189m~3/h, and rise5.1％compared to the original air duct of1132m~3/h, and the level of noise is reduced by0.6dB.Comparative study of the structure of bell mouth used in the multi-blade centrifugal fanwas implemented. This three bell mouths are as follows: The first type of bell mouth is theinward inlet used in the original air-conditioner. The second type is the inward inlet whoseaxial height is larger than the first type. The third type is the new mold line inward inlet withsmaller slope angle than the first type. Calculation results show that the latter two types ofbell mouth can improve airflow utilization ratio and reduce the vortex in the back of voluteexit comparison to the first type and raise the air volume by4.7%and3.6%respectively.The experiment was carried out to validate the result of simulation and the experimentalresults show that the air volume can increase by3.8%and2.2%respectively. Meanwhile thelevel of noise is invariant. The circulating air volume of the floor standing air-conditionerused the two types are both improved.The optimum designs for the structure of impeller is mainly about substitution ofstraight blade by serrated blade，which can break maelstrom produced by blade trailing edge into smaller vortex. The aerodynamic noise was forecasted by F-fowcs Williams-Hawkings equations. The numerical results show that air volume flow of novel fan is theapproximately same as the original air duct, while noise level decreases16.3%, which hassignificant improvement of aerodynamic performance.