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矿井定常湍流脉动对通风阻力测试影响的理论分析 被引量:11
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作者 刘剑 李雪冰 +2 位作者 陈廷凯 宋莹 赵春双 《中国安全生产科学技术》 CAS CSCD 北大核心 2016年第5期22-25,共4页
受湍流脉动影响,矿井通风阻力测试结果的数值波动是不可避免的。为探究湍流脉动对通风阻力测试的影响程度,以压差计测阻法为例进行理论分析。根据阻力测定原理和能量方程,在定常圆管流动条件下,导出湍流脉动影响下倾斜压差计测量示值波... 受湍流脉动影响,矿井通风阻力测试结果的数值波动是不可避免的。为探究湍流脉动对通风阻力测试的影响程度,以压差计测阻法为例进行理论分析。根据阻力测定原理和能量方程,在定常圆管流动条件下,导出湍流脉动影响下倾斜压差计测量示值波动范围的计算表达式;理论分析测试巷道的断面尺寸和风速大小对数值波动幅度和测试精度的影响。结果表明,压差计示值的波动幅度与当地湍流强度及风速的平方成正比;巷道风速的量级是压能波动的主导因素,测试风速越大,液面数值涨落幅度越大,波动现象越明显;而数值波动幅度大不等同于测试精度低,小断面大风速巷道中易获得满意的测试精度而大断面巷道中无论风速高低均不易获得较高测试精度。为减小湍流脉动造成的通风阻力测试的随机误差,需在短时间内进行多次测试取统计平均结果,这在大断面巷道的阻力测试中尤为重要。 展开更多
关键词 安全 湍流脉动 通风阻力测试 压能波动 测试精度
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Longitudinal type-line optimization of high-speed train for low aerodynamic noise 被引量:4
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作者 肖友刚 杨群 +1 位作者 孙亮 时彧 《Journal of Central South University》 SCIE EI CAS 2014年第6期2494-2500,共7页
The basic head shape of high-speed train is determined by its longitudinal type-line(LTL),so it is crucial to optimize its aerodynamic performance.Based on the parametric modeling of LTL constructed by non-uniform rel... The basic head shape of high-speed train is determined by its longitudinal type-line(LTL),so it is crucial to optimize its aerodynamic performance.Based on the parametric modeling of LTL constructed by non-uniform relational B-spline(NURBS)and the fluctuation pressure obtained by large eddy simulation(LES),the Kriging surrogate model(KSM)of LTL was constructed for low aerodynamic noise,and the accuracy of the KSM was improved gradually by adding the sample point with maximum expected improvement(EI)and the optimal point from optimization.The optimal objective was searched with genetic algorithm(GA).The results show that the total fluctuation pressure level(FPL)of the optimal LTL can be 8.7 dB less than that of original one,and the shape optimization method is feasible for low aerodynamic noise design. 展开更多
关键词 longitudinal type-line non-uniform relational B-spline (NURBS) aerodynamic noise fluctuation pressure level (FPL) shape optimization
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