| The implementation of favorable policies such as the “One Belt and One Road” in the international market and the structural reform of the domestic supply side has greatly broadened the sales market for construction machinery products.In addition,increasingly stringent pollutant emission regulations at home and abroad have prompted related companies to accelerate the pace of product replacement.In addition to the harsh working environment,low operating speed,large number of heat source systems,and high pollutant concentrations in the exhaust gas,high-power engines impose higher requirements on the cooling capacity of the vehicle's cooling system for construction machinery.Therefore,it is one of the research hotspots in the field of engineering machinery thermal management by designing and developing an efficient cooling system and cooling module to improve the thermal management level of the vehicle,enhancing the fuel economy and power of the vehicle,and reducing the emission of pollutants.This article relies on the national support plan science and technology project “Integrated Intelligent Construction Machinery Equipment Development for Energy Saving and Safety”,and takes the loader vehicle equipped with a double circulation cooling system cooling module as the research object,adopting a combination of numerical simulation and experimental research methods.The flow field and heat transfer characteristics of the new heat dissipation module assembly under typical working conditions,as well as the aerodynamic performance and aerodynamic noise of the cooling fan unit were analyzed and improved.The research work done in this paper provides guidance for engineering practice The main research content of the full text includes the following aspects:Firstly,the theory of Computational Fluid Dynamics(CFD)simulation technology and the structure and working principle of the dual-circulation cooling system and its compact heat dissipation module are introduced.A simplified three-dimensional model of a 50-type loader equipped with a dual-circulation cooling system cooling module under a virtual wind tunnel was established.The boundary conditions and solution methods of the Fluent numerical simulation were determined according to the design parameters of the cooling system cooling module of the double-circulation cooling system.The internal air velocity field and temperature field distribution characteristics of the cooling module were analyzed.Secondly,the accuracy of the simulation results of the virtual wind tunnel simulation model is verified by the heat balance test of the loader,and the influence of altitude on the heat transfer performance of the heat dissipation module is predicted by the CFD software.Further,the influence of the space between the cooling fan and the radiator,the form and position of the fan and the cooling fluid flow path in the radiator on the performance of the new heat dissipation module have been studied,which provides guidance for the optimization of the performance of the product in the engineering.Thirdly,the performance simulation model of the cooling fan is established,and the reliability of the simulation method is verified by comparing the simulation data of the circular curved plate fan with the experimental data.Based on the flow pressure loss characteristics of a new type of radiator,a cooling fan of CLARKy airfoil curve is designed under the guidance of the theory of isolated airfoil and variable loop parameter design method.The aerodynamic performance and aerodynamic noise performance of the CLARKy airfoil cooling fan are predicted by CFD simulation.The simulation results show that the variation trend of the total pressure,static pressure and static pressure of the CLARKy airfoil fan with the flow rate is consistent with the overall trend of the circular curved fan.When the air flow is less than 9.11 m3/s,the CLARKy static efficiency of the airfoil fan is higher than that of the circular curved plate fan,but with the increase of the flow rate,the difference between the two fans becomes smaller.When the speed is 2000r/min,the total sound pressure level of CLARKy is 95.15 d B,which is 3.42% lower than that of the circular curved fan.Finally,for the CLARKy airfoil fan,the influence of the blade angle unequal distribution,the split blade and the top ring of the blade on the aerodynamic performance and aerodynamic noise of the fan is studied,which provides a reference for the optimization of the fan performance.4 groups of three dimensional model of heat dissipation module based on different airfoil fans are established.The results of CFD simulation show that they play an active role in improving the air velocity uniformity of the rear grid outlet of the power cabin. |
PDF Full Text Request