Simulation And Analysis Of Flow Field In Closed Quenching Tank

Quenching tank is one of the important equipment in the production process of heat treatment.With the constant progress of heat treatment technology and the strict heat treatment requirements of quality,safety and environmental protection,quenching tank is going towards the multi-function and automation as well.For an top quality of quenching tank,a certain flow velocity,cooling ability and uniform distribution of flow velocity in quenching medium are required to decrease the harm of quenching distortion and cracking.Due to the openness of quenching tank,the turbulence state of medium in the quenching tank and the lack of measurement methods,it’s very difficult to analyze the quenching process.Therefore understanding the flow field distribution of medium in quenching tank by numerical simulation and the effect of different factors on medium flow field distribution has an important application value in improving quenching products quality and quenching process design.According to the concrete structure and size of quenching tank,taking the quenching tank with closed mixing device as the research object,the model of quenching tank was established through Pro /Engineer 5.The mesh generation and simulation calculation of the quenching tank was obtained based on the dynamics simulation software Fluent under ANSYS Workbench platform.Through the post-processing visual analysis of simulation results,the flow field distribution with flow-equalizing device and without flow-equalizing device and the change of effective quenching zone in the quenching tank with different inlet velocity were obtained.At the same time this paper analyzed quenching tank under different temperature of QA55 quenching oil and different concentration of Ca Cl2 solution,and the change of flow field in quenching tank under loading work piece was also obtained.(1)Through the analysis of flow field in quenching tank with and without flow-equilibrating device,it was found that the flow field distribution in the quenching tank was verticity before installing flow-equalizing device,effective quenching zone of the flow field has enlarged with flow-equalizing device,and velocity distribution of quenching medium was more uniform in flow field.Through the research on the effect of flow-equalizing device on the flow field uniformity in the quenching tank,the results can pave the way in quenching tank flow field for further analysis.(2)With different inlet velocity in the boundary conditions of water,oil quenching and Ca Cl2 solution for the three kinds of quenching medium,it can be found that increase quenching tank inlet velocity can’t change the distribution of flow field but can partially decrease eddy current distribution area.Too large inlet velocity can increase the velocity difference of quenching medium in the bottom of the quenching tank and the uniformity of flow field distribution.Proper inlet velocity can be obtained by the research on simulation results and experimental analysis.The kinematic viscosity of QA55 quenching oil itself makes the eddy current area increase in the quenching tank flow field.Enlarging the temperature of quenching oil to reduce the kinematic viscosity is beneficial to the fluidity of quenching oil and can also widen effective quenching area in quenching tank,but increasing the concentration of Ca Cl2 solution can decrease the eddy current area in the quenching tank.(3)The eddy region increases with loading work piece in the quenching tank,and the original uniform flow field is broken.The eddy region decreases and shifts down with the increasing number of loading work piece,but the velocity around the lower work piece increases and distributes unevenly with the depth increased.Therefore,a hollow slab fixture closed to its area can be added at the bottom of work piece in practical production in order to reduce the deformation and cracking of work piece.