| The cooling system is an important part of the loader.The engine system,transmission system and hydraulic system need to work in the proper temperature range.The high temperature will reduce the reliability of the system resulting in leakage and other issues,affecting the normal work of the loader.The low temperature will reduce fuel efficiency,increase the power consumption of system.The engine power demand of loader is really enormous as a construction machinery,the engine output power should be mainly used in the loader working system in order to reduce the power consumption of other systems,to achieve the role of energy-saving and emission reduction,therefore,through control of the cooling system so that the cooling system work in the best temperature range,reducing the cooling system power consumption and improving loader efficient and reliable operation is of great significance.Based on the cooperative project of school and enterprise,this paper studies the independent cooling system of the loader by means of theoretical research and numerical simulation.The heat transfer characteristics of the loader cooling system are studied by one-dimensional and three-dimensional coupled simulation.The data of the loader cooling system based on the principle of minimum power consumption of the cooling system is established to realize the independent cooling of the loader.The main contents of this paper are as follows:(1)Based on the first law of thermodynamics and heat transfer theory,the heat dissipation of a certain radiator engine is calculated.The parameters of the fan,water pump,hydraulic pump and hydraulic motor are matched according to the heat dissipation.(2)Using the CFD simulation software Fluent to analyze the sub-working conditions of the loader cooling system,the flow field characteristics and the temperature field characteristics inside the power tank are obtained,and the relationship between the air flow rate and the fan speed is obtained.Simulation of the boundary conditions,and loader powertank structure on the impact of thermal system to study.(3)One-dimensional simulation model of loader cooling system is established by one-dimensional simulation software AMESim,and the fan air volume obtained by 3D simulation is used as one-dimensional simulation boundary condition to realize coupling simulation.The internal temperature characteristics of loader cooling system are obtained by one-dimensional simulation The And the relationship between the heat dissipation-air-liquid temperature difference-air flow and coolant flow rate of the loader cooling system is obtained based on the one-dimensional simulation,which is used as the cooling system to control the boundary conditions.(4)The control strategy of the loader cooling system based on the minimum power consumption of the cooling system is established.The relationship between the fan speed and the cooling system power consumption,the cooling power and the ambient temperature is obtained by simulation.Based on the principle of minimum power consumption,a MAP chart of fan / pump speed-heat dissipation-ambient temperature was established.A complete independent cooling system control model was built by PID feedback control.Through AMESim-Simulink,the simulation results show that the temperature of the cooling system is in the optimum temperature range,and the feasibility of the anti-cooling control strategy is demonstrated by simulation and verification of different cooling conditions and ambient temperature. |
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