高速水射流粉碎中射流冲击区水垫的增阻效应

摘要

为了解高速水射流冲击区特性和对物料粉碎效果的影响,通过理论分析、数值计算方法和采用自主研制的后混式高压水射流粉碎装置进行粉碎实验（以煤为粉碎物料）,针对水射流在冲击区产生的水垫及其对物料粉碎的影响进行了研究。结果表明：高速水射流在靶体冲击区范围内存在水垫,水垫范围约为10倍喷嘴半径r0;射流冲击区水垫对粉碎不利,在有水垫增阻情况下,水垫对粉碎效率具有一定影响,特别是对低粒级产品减产影响明显;无水垫增阻情况下,物料粉碎较前者更加高效,产率也更高;研究水射流冲击区水垫增阻减产机理,对高速水射流粉碎技术及设备研究实践具有一定理论和设计参考价值。%In order to understand the characteristics of high-speed water jet impact zone and effect of material crushing,the research on water cushion in impact zone and influence of material crushing has been conducted according to the theoretical analysis,numerical computation and high pressure water jet smash experiment results obtained from a self-designed afterward mixing facility with coal as main crushing material.The result shows that there is a water cushion with about 10 times of r0 in the range of target body impact area of high-speed water jet.The water cushion of the jet impact zone is unfavorable for the crushing.There is certain effect on the crushing efficiency especially on the reduction of the low size fraction level product with increased resistance of water cushion.It is more efficient without increased resistance of water cushion.Research about increased resistance of water cushion to the reduction mechanism of water jet impact zone provides certain theory and design reference to the research practice on water jet crushing technology and equipment.