Research On Aerodynamic Characteristics For Cooling Fan Of Construction Vehicle

Research on Aerodynamic Characteristic for Cooling Fan of Construction Vehicle Automotive cooling fan is an important branch of the cooling fan and widely used in vehicle cooling system such as automobile, engineering machinery and military machinery. With National Science and Technology Support Programme Project "Energy-saving and safety-oriented, integrated engineering machinery and equipment research and development"(project number:2013BAF07B04),this paper research on Aerodynamic Characteristics for Cooling Fan of Construction Vehicle. In engineering vehicles, the main roles of cooling fan are create air flow environment for the engine compartment, provide sufficient cold air flow to the radiator module, ensure the cooling requirements of the vehicle engine system, hydraulic system, transmission system and air conditioning system, maintain smooth continuous operation of each subsystem of the vehicle and keep the vehicle dynamic and economic performance stable and reliable.Firstly, in this paper, the performance of cooling fan is studied through FLUENT software. Fan duct and fan wind chamber model are established respectively and analyzed the performances of cooling fan and its accessories. Of which, the fan wind chamber model is a three-dimensional simulation model established for the fan test performance according to national standards. Through simulating the test conditions, combined with the MRF method, the performance of arc bending plate fan provided by a manufacturer is simulated and compared with the experimental data. Fan wind chamber model is a three-dimensional model established for the analysis of the performance of the cooling fan with the auxiliary member on the basis of relevant references. This model introduces a radiator model to evaluate the change in performance of the fan in the auxiliary member through the radiator performance change.Secondly, simulated and analyzed influences of the changes of the main structural parameters such as arc bending plate fan installation angle, the blade chord length, radius of curvature of the blades, hub ratio and blade height, etc. to the performance of cooling fan in the fan wind chamber model. Combined with orthogonal test method and signal-to-noise ratio method, analyzed the sensitivity of each structural parameter to the performance of the cooling fan, which is installation angle, the blade chord length, radius of curvature of the blades and hub ratio from high to low. The performance influence of sinking degree and radial clearance change of the cooling fan and the auxiliary member and the commonly used top ring structure in the arc bending plate fan are analyzed. Conclusion:when the sinking degree and radial clearance change are36mm and5mm respectively, arc bending plate fan with the auxiliary member performs the best, and the performance of top ring arc bending plate fan is improved as well.Thirdly, simulated and analyzed on the parameters change of fan airfoils in the fan duct model. Utilizing4types of airfoils-arc curved plate airfoil, LS airfoil, NACA6506airfoil and NACA6512airfoil, the relationship between airfoil lift coefficient and fan performance. The simulation illustrates that compared the other3airfoils, NACA6512airfoil has a better aerodynamic performance. According to the circular plate bending fan test data, the cooling fan is designed and simulated with isolated airfoil method and NACA6512airfoil, the designed fans can reach the design performance value. Forward bending processing in the designed fans, the flow rate from forward-bended fan is slightly less than the design fan, but have better static pressure performance. Through the simulation of designed fan and forward-bended fan and compared with the arc bending plate fan, it can be shown that the designed fan has the best performance with the auxiliary member. Consequently analyzed the sinking degree and radial clearance change of the designed fan with the auxiliary member and concluded that when the sinking degree and radial clearance change are24mm and5mm respectively, arc bending plate fan with the auxiliary member performs the best.Finally, take the50wheel loader engine compartment from some factory as the research object, identified four kinds of programs. Contrast the engine compartment fluid properties and heat transfer performance of the programs, and assessed the influence of designed fan and auxiliary member improvement to the fluid properties and heat transfer characteristics.