Research Of Low-Noise Cooling Fan Design In The Engine Compartment Of An Asphalt Paver

With the expansion of domestic cities and the development of economy,road construction has become an important support,working as an indispensable part in road construction,standard has grown higher in each aspect of asphalt pavers.Build up as an environment for the power system of an asphalt paver,the heat dispersion of the engine compartment concerns the proper functioning of the power system,while most of the driving cab is not well-encapsulated and provide poor sound proof,therefore the noises radiated from the engine compartment will impair the health of workers.Speaking of the components of a heat dispersion system,mainly it is an axial flow cooling fan combines a set of radiators,and the aerodynamic and noise characteristics of an axial flow cooling fan plays an important role in each aspect.Reasons concerned above,the flow field features and noise characteristics of an axial flow fan was analyzed and optimized designed in this research.At the first of all the works,the flow field features and aerodynamic characteristics of the axial flow fan were analyzed in a wind tunnel model under actual working condition,there followed an optimization of tip-clearance in attempt to improve the flow at tip position.Compared to the results of the origin one,tip-clearance optimization did not work dramatically on the promotion of mass flow rate,merely increased by 1.0%,so was the efficiency,which slightly increased by 1.3%,aside from these,the vortex area below the fan was obviously reduced.Afterwards,aimed at the disadvantages of the original fan,the airfoil theory and variable circulation design method was thus applied,two types of fans were calculated to adapt to the condition of the engine compartment,respectively with 9 blades and 10 blades.In flow field calculation and comparison of the designed ones,it was discovered that the 9-blade one excels the 10-blade one in every aspect,as its flow rate is 16.8%higher and total pressure efficiency 8.2%higher,plus less vortex near the fan,in that case 9-blade one was chosen as a specific-analyzed objective for noise characteristics.In the final study,the original fan and the 9-blade fan were both modeled inside an engine compartment,and the noise performances were analyzed and compared,results showed that the BPF of 9-blade fan occupied non-major part in the overall noise frequency,and the vortex noise SPL reduced by 10dB,therefore noise reduction effect of variable circulation designed 9-blade fan is quite apparent in simulation.