Study On Grooved Wick Of Load-bearing Plate Type Multi-channel Heat Pipe

In order to solve the problem of oil film thermal control of the hydrostatic thrust bearing inside the machine tool,a variety of heat pipe wick structures were compared.Finally,it is found that sintered wick structures and composite wick structures are easily damaged by the external forces.Such a heat pipe is difficult to withstand heavy loads.Therefore,this dissertation proposes a flat multi-channel heat pipe with a grooved liquid wick that can be processed by a ploughing-extrusion method with the use of the self-designed multi-tooth cutter.In the meanwhile,it can study the surface morphology of the groove.Since the heat transfer characteristics of heat pipes are mainly determined by eight heat transfer limits,this thesis selected five suitable heat transfer limits for mathematical modeling according to the room temperature conditions,then designed a method that can optimize the geometric parameters of the groove.The best groove geometry is obtained by calculation and data screening.The optimized geometry parameters of the grooves were simulated by the computational fluid dynamics method for gas-liquid two-phase flow,specifically the liquid evaporation,condensation and the movement and temperature changes of steam molecules.Then,using the optimized groove as a reference.In this part,various tool configurations were compared,and a multi-tooth tool was designed.In order to study the pear-cutting-extrusion process intuitively,the numerical simulation of pear-cutting-extrusion process was carried out.First,a single-tooth cutter structure model of pear-cutting was established,and the finite element pear-cut simulation was performed by using Deform 3d software to obtain the force curve changes in the three directions of x,y,and z.The winged state and the arc shape of the wick structure clearly shows that the secondary groove construction is easily generated by the function of multiple teeth.Then,it comes to the processing stage of the flat heat pipe groove.On a 300x20 mm cross section of a copper plate with a volume of300x200x20 mm,a gun drill was used to drill a depth of 200 mm to make sure the dimensional tolerance within the required accuracy range.Next,the bearing steel(GCr15)was heat-treated,and then multi-tooth tools were processed by wire electrical discharge mechining,and the tools were sharpened and cleaned according to the angle requirements.The realization of pear-cutting also requires the proper design and manufacture of tool holders for clamping multi-tooth tools.At the same time,a pear-cutting and extrusion processing platform was set up to clamp the copper plate and the cutter bar.The use of a hand-operated hydraulic jack can solve the problem of large strokes and provide a large pear-cutting force for multi-tooth tools.The designed multi-tooth cutter has a length of 10 mm,the cross-section of the single ploughing edge in the multi-tooth cutter is an isosceles trapezoid.The angle between the sides of the single tooth is 120,the number of teeth is 55,the height is0.32 mm,the number of divisions is 6.545.Multi-tooth cutter with top edge width of 0.31 mm,tooth bottom edge width of 0.32 mm,and rib width of 0.32 mm.Pear cutting — if the pressing speed is too fast,the cutter bar will be damaged.However,if it is too slow,the cutting effect will not be obvious.It is best to plow and squeeze at a speed of50mm/min.Finally,the image analyze of the Extrusion-ploughing grooves of the heat pipe was carried out.The results show that the capillary structure of the ploughing-extrusion groove is better than that of the groove cut by wire electrical discharge mechining.