Computer Simulation Of Quenchant Flow Field In Quenching Tank With Agitation System

A quenching tank with agitator system and flow-equalizing equipment was selected to simulate the flow field in it. First, 3-D model of quenching tank is set up and meshed in the professional pre-processor GAMBIT. And then k- ε two equations model was selected as the mathematical basis of quenchant judging from the motion of quenchant in the quenching tank. Then the professional CFD software was used to compute the problem, the 3-D flow field in the quenching tank was obtained finally. The characteristics of quenchant flow field and the influence of flow-equalizing equipment were analyzed; the concept of "effective quenching zone" was put forwards, and the difference of flow field among water, bright quenching oil and polymer solution were compared. The influence of variation of inlet speed, oil temperature and concentration of polymer solution on the distribution of flow field in the quenching tank was also analyzed.The simulation results show that: the distribution of quenchant flow field in the quenching tank is non-uniform, an upwind uniformity flow will be formed in the quenching tank due to the reflection of the flow-equalizing equipment, a turbulent swirl also comes into being at the same time and the speed in the center of swirl is very low. Then the local uniform zone can be determined as the effective quenching zone, parts being quenched in this zone can get desired microstructure and performance. Variation of location and dimension of the flow-equalizing equipment will affect the distribution of effective quenching zone.Increasing of quenching tank inlet speed will not change the characteristic distribution of quenchant flow field, but can results in aggravation of un-uniform flow field in the quenching tank. As for bright quenching oil, the directivity of oil flow is very significant in the quenching tank and its effective quenching zone is much narrower than water because its kinematic viscosity is much bigger than the latter. The kinematic viscosity of oil will change greatly with variation of temperature, the higher using temperature the lower kinematic viscosity. Turbulent flow of oil will be developed sufficiently with high temperature, and its effective quenching zone will also be broadened simultaneously. There is little difference between the distribution of diluted polymer solution PAG.The simulation of quenchant flow field in 3-D quenching tank can give both velocity vectors at arbitrary position and the integrated flow field distribution in it. This work can help to determine the effective quenching zone in real operation and will improve the quality of parts being quenched. The simulation will also promote the level of quenching tank design especially.