Numerical studies on transient heat transfer characteristics of air-array-jet impingement with a small jet-to-plate distance and a large temperature difference between nozzles and plate were presented.The dimensionles...Numerical studies on transient heat transfer characteristics of air-array-jet impingement with a small jet-to-plate distance and a large temperature difference between nozzles and plate were presented.The dimensionless jet-to-plate distance(H/D)was 0.2,and non-dimensional nozzle-to-nozzle spacing(S/D)was 3,4,5 and 6,respectively.It is found that the quenching time is shortened at a constant total mass flow at air jet inlet m·(m·=218.21 kg/h),and the heat transfer uniformity is deterio-rated as S/D increases.However,the adding reversed-flow nozzles can shorten the quenching time of the glass plate considerably with a modest change in the heat transfer uniformity.The results at variable m·are the same as those at a fixed m·.Furthermore,the parity and arrangement of nozzles are also discussed,It is found that an odd number of nozzles is more beneficial for transient heat transfer.Based on these results,an appropriate proposal for ultra-thin glass tempering process is presented.展开更多
提出了一种新颖的用于测量微结构力学性能的弯曲测试法——微射流驱动的弯曲测试法(microjet-driving microbending test method,JDBT)。该方法利用气体微射流连续冲击微结构,使之发生弯曲变形,通过获取结构的尺寸参数和形变位移,并代...提出了一种新颖的用于测量微结构力学性能的弯曲测试法——微射流驱动的弯曲测试法(microjet-driving microbending test method,JDBT)。该方法利用气体微射流连续冲击微结构,使之发生弯曲变形,通过获取结构的尺寸参数和形变位移,并代入结构的变形公式,从而反解出材料的力学性能参量。利用动量定理推导了微射流作用力公式,对某型号石英摆片式加速度计的敏感结构进行了理论建模,并用COMSOL MULTIPHYSICS有限元软件对理论公式进行了修正,接着通过JDBT实验得到了不同流量下的结构位移,最后将结构尺寸和结构形变位移代入修正后的理论公式,从而得到了石英玻璃的弹性模量约为71GPa,比纳米压痕仪测试的结果要小14%左右,与文献中提到的结果吻合较好。展开更多
基金Natural Science Foundation of China(51335002,51905049)。
文摘Numerical studies on transient heat transfer characteristics of air-array-jet impingement with a small jet-to-plate distance and a large temperature difference between nozzles and plate were presented.The dimensionless jet-to-plate distance(H/D)was 0.2,and non-dimensional nozzle-to-nozzle spacing(S/D)was 3,4,5 and 6,respectively.It is found that the quenching time is shortened at a constant total mass flow at air jet inlet m·(m·=218.21 kg/h),and the heat transfer uniformity is deterio-rated as S/D increases.However,the adding reversed-flow nozzles can shorten the quenching time of the glass plate considerably with a modest change in the heat transfer uniformity.The results at variable m·are the same as those at a fixed m·.Furthermore,the parity and arrangement of nozzles are also discussed,It is found that an odd number of nozzles is more beneficial for transient heat transfer.Based on these results,an appropriate proposal for ultra-thin glass tempering process is presented.
文摘提出了一种新颖的用于测量微结构力学性能的弯曲测试法——微射流驱动的弯曲测试法(microjet-driving microbending test method,JDBT)。该方法利用气体微射流连续冲击微结构,使之发生弯曲变形,通过获取结构的尺寸参数和形变位移,并代入结构的变形公式,从而反解出材料的力学性能参量。利用动量定理推导了微射流作用力公式,对某型号石英摆片式加速度计的敏感结构进行了理论建模,并用COMSOL MULTIPHYSICS有限元软件对理论公式进行了修正,接着通过JDBT实验得到了不同流量下的结构位移,最后将结构尺寸和结构形变位移代入修正后的理论公式,从而得到了石英玻璃的弹性模量约为71GPa,比纳米压痕仪测试的结果要小14%左右,与文献中提到的结果吻合较好。
