Validation of a single component gas quenching model

Abstract
An extensive CFD modelling study of cooling using nitrogen jets showed that an array of high velocity gas jets close to the part surface could produce cooling at a similar speed to oil. The optimum conditions were: an approximately uniform nozzle field with the jets four to eight times their own diameter apart at a distance from the part to be quenched of a quarter of the diameter of the jets; and a jet velocity of 100 m/s. When the optimised conditions were applied to an idealised gear form, the model suggested that it could be fully hardened if a nitrogen/hydrogen mixture was used. The use of the model had dramatically reduced the time to discover the optimum conditions but no validation experiments had been carried out. Before proceeding with any commercial applications, the model was validated using a physical test rig. It showed that the model was very close to reality and that the results of modelling could be used to predict the behaviour of production parts.