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标定系统密闭室壁面温度差诱导流动研究
Research on Flows Induced by Wall Temperature Difference in an Enclosed Chamber of a Calibration Facility
投稿时间:2022-01-11  修订日期:2022-07-11
DOI:
中文关键词:  (5号楷体)极低风速  标定系统  密闭室  壁面温差  诱导流动  数值模拟  实验观察
英文关键词:extremely low speed  calibration facility  enclosed chamber  wall temperature difference  induced flow  numerical simulation  experimental observation
基金项目:
作者单位邮编
周廷波 中国空气动力研究与发展中心 设备设计与测试技术研究所 621000
王欧 西北工业大学 翼型叶栅空气动力学国家重点实验室 710072
张正科 西北工业大学 翼型叶栅空气动力学国家重点实验室 710072
田永强 西北工业大学 翼型叶栅空气动力学国家重点实验室 710072
张国彪 中国空气动力研究与发展中心 设备设计与测试技术研究所 
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中文摘要:
      标定系统温度控制加热管路可能存在加热的不对称性或不均匀性,导致上下壁面存在温度差,这个温度差可能诱发密闭室空气的扰动流动。而密闭室作为热线探头标定时运动的空间,其中的空气必须在探头起动前处于静止状态,否则,如果出现不期望的干扰流动,将会影响标定的精度。通过求解N-S方程对上下壁面存在温度差的密闭室流场进行数值模拟,考察温度差诱发的扰动速度场及其对标定的影响,同时用实验方法借助悬挂的丝线的摆动观察壁面温度差引起的诱导流动。计算结果表明,温度差诱发的比较大的速度都出现在密闭室壁面附近一个薄层内,且其量值小于设计指标要求的误差限,在其余的区域,也就是热线运动的区域,诱导的扰动速度都比设计指标要求的速度误差上限小一个量级,不影响标定精度;实验观察也证实,在密闭室上下壁存在温度差的情形下,肉眼观察不到丝线的摆动,说明扰动流动即使有,也量值很小,不影响标定精度。
英文摘要:
      There might be asymmetric or non-uniform heating in the heating pipeline arrangement for temperature control in a calibration facility, thus resulting in temperature difference between the top and bottom walls, This temperature difference may induce disturbing flow of air in the enclosed chamber of the calibaration facility. As the space for a hot wire probe to move in when being calibrated, and the air in the chamber must be in a stagnant state before the probe is started; otherwise, the accuracy of calibration will be affected if the unexpected disturbing flow occurs. The flow field in the enclosed chamber with temperature difference between top and bottom walls was numerically simulated by solving the Navier-Stokes equations, and the disturbing velocity field induced by the temperature difference and its influence on calibration were investigated. Meanwhile, the induced flow caused by wall temperature difference was observed by means of the swing of a suspended thin silk thread. The computed results show that the maximum velocity induced by the temperature difference occurs in a thin layer near the wall of the enclosed chamber, and its magnitude is less than the error margin required by the design criteria. In the rest area in the enclosed chamber containing the zone where the hot-wire probe moves, the induced velocity is one order of magnitude less than the velocity error margin stipupated by the design criteria, which does not affect the calibration accuracy. Experimental observation also confirmed that when there exists temperature difference between the top and bottom walls of the enclosed chamber, the swing of the silk thread could not be observed by naked eyes, indicating that the disturbing flow, even if it exists, has a small magnitude and does not affect the calibration accuracy.
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