Research On Channel Structure Optimization Of Compressor Blade Repairing Fixture Based On Enhanced Heat Transfer Theory

The rapid development of civil aviation has greatly improved the market competitiveness of the civil aviation maintenance industry.The aero compressor blades as one of the core components of aero-engines,have poor working conditions and various forms of damage.In order to improve the current status of foreign repairs of damaged blades and reduce maintenance and operating costs,it is necessary to develop automatic repair equipment for aviation compressor blades with independent intellectual property rights.It is imminent and the flexible fixture is the key component.TC4 titanium alloy reacts easily with N,H,O,and C elements in the environment at high temperatures?above350??,producing byproducts that affect the quality of the weldment.The faster cooling rate reduces the content of impurities in the weld,and at the same time,it can also increase the density of the microstructure of the fine acicular martensite?'phase of the weld and the heat-affected zone,thereby improving the mechanical properties of the weld.In order to ensure the welding quality of the weldment,this article is devoted to the study of the structure of the water-cooled channel and its optimization of physical and geometric parameters for microplasma arc welding repair fixtures,in an effort to improve the cooling rate of the weldment.A detailed derivation process for convection enhancement heat transfer is presented to guide the channel optimization.The convective heat transfer enhancement mechanism in a single-phase medium indicates that the enhanced heat transfer effect of increasing the cooling water normal velocity v on the wall surface is more obvious than increasing the cooling water main stream velocity u.The reason is that the thermal boundary of the cooling water is destroyed,and the mixing of the mainstream and the boundary layer is greatly enhanced.The field cooperation principle points out that the enhancement of convective heat transfer is essentially to increase,that is,to reduce the synergy angle between the temperature field and velocity field of the cooling water.A complete finite element model was established to numerically simulate the welding repair process.The temperature of the weldment during welding was measured and recorded using a high-definition infrared thermography.Compared with the simulation results,the maximum error was 4.57%and less than 10%,thus validating the correctness of the established model.The results show that the optimal flow rate of cooling water is5L/min,and the optimal inflow temperature is 10°C.Under this condition,the high temperature duration t=3.542s,and the cooling water takes away the heat Q=41.0478J per unit of time.In terms of the channel structure,the thread pitch P,the width A of the tooth bottom,and the height H of the tooth profile are reasonably limited.By comparing the simulation results of the light hole channel and the helical channel,the P,A,and H are optimally analyzed.The results show that t increases with the increase of P and A,decreases with the increase of H,and the trend of Q is opposite to that of t.At the same time,the influence of each parameter on the heat transfer and flow resistance characteristics of the cooling water was analyzed,and the evaluation results were evaluated using the enhanced heat transfer performance evaluation criteria.When P=6mm,A=2mm,and H=1.2mm,the weldment has the best cooling effect.Compared with the light hole channel,t is shortened from 3.542s to 3.153s,the amplitude is 10.98%,and Q increases by 20.7291J.Nu increased by 52.90%,enhanced heat transfer evaluation standard PEC takes a maximum of 1.249.