An extensive modelling study of cooling by means of nitrogen jets showed that an array of high velocity gas jets close to the surface of the part could produce cooling at about the same rate as oil. The optimum conditions required an approximately uniform nozzle field with the jets very close to the part and a gas velocity of 100 m/s. When these optimised conditions were applied to an idealised gear form, the model suggested that it could be fully hardened when a nitrogen-hydrogen mixture was used. Calculation suggested that in this type of nozzle field the part would float between the arrays, eliminating the need for fixturing. Up to this point all the work had used CFD modelling. This type of modelling dramatically reduced the time taken to discover the optimum conditions but it had not been validated by experiment. Before it could be given a commercial application, the model had to be validated using a physical test rig. This showed that the model gave results very close to reality, which could predict the behaviour of production parts.
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机译：广泛的利用氮气流冷却的模型研究表明，靠近零件表面的一系列高速气体流可以以与油相同的速率产生冷却。最佳条件要求喷嘴场近似均匀，喷嘴非常靠近零件，并且气体速度为100 m / s。当将这些优化条件应用于理想齿轮时，该模型表明，当使用氮-氢混合物时，它可以完全硬化。计算表明，在这种类型的喷嘴场中，零件将在阵列之间浮动，从而无需固定装置。到目前为止，所有工作都使用了CFD建模。这种类型的建模极大地减少了发现最佳条件所需的时间，但尚未通过实验验证。在将其提供商业应用之前，必须使用物理测试台对模型进行验证。这表明该模型给出的结果非常接近实际，可以预测生产零件的行为。
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