| With gradually larger power of engineering vehicle,as the core of the the engineering vehicle,the cooling system has an important influence on the overall performance and service life of the vehicle,so the performance requirements are raised.The power cabin entropy evaluation system has been established based on the second law of thermodynamics,which could evaluate the performance of cooling system.The research and improvement of the cooling system have been performed by numerical simulation and the main studies are listed as the following aspects.The process of the air flowing through the engine compartment has been introduced,in the cooling system,the most significant factors on the entropy production of air flow through the power module are the cooling system radiator and cooling fan.Based on the second law of thermodynamics and the performance of the radiator and the cooling fan,the entropy production model of air flow in power cabin has been built,which provides a new method for performance evaluation of cooling system;large horsepower grader has been built by 3D modeling software,the numerical simulation has been performed after setting the mesh and boundary conditions,obtaining the import and export flow and heat dissipation of the engine compartment.For verifying the accuracy,the simulation results are compared with the experimental data.Then combined with the simulation data of the radiator and cooling fan,the entropy production of the air flow in the engine compartment;numerical simulation method combined with the method of orthogonal test and the Taguchi method,has been performed for combining and simulating the air flow area of engine compartment,the ambient temperature and the cooling fan speed.The entropy production of air flow in engine compartment under different combinations has been calculated,by the analysis of signal-to-noise ratio and calculating the contribution rate,some improvement methods for cooling system have been provided.Through the contribution rates of different parameters and the effects on entropy production of power cabin,firstly,the performance of cooling system has improved after increasing the gas inlets.Secondly,the increasing of power cabin partition has been analyzed.Finally,by increasing the gas inlets,raising the fan speed and adding the power cabin partition,the comparison of entropy production of air flow in engine compartment has been performed,ensuring the effectiveness of the improving methods. |
