Measurement of velocity vector in gas stream

A method of determining the three-dimensional vector of mean velocity in a gas stream with a three-wire probe and a constant-current thermoanemometer has been developed and experimentally evaluated.     

海洋矢量声场观测浮标与潜标系统

构建了一个以三维低频矢量传感器为核心的海洋矢量声场观测用浮标与潜标系统平台。水下潜标系统对矢量传感器拾取的声场声压与质点振速共4路信号进行预处理,并进行采集、解算与自存储。矢量传感器的水下姿态由潜标中电磁姿态仪给出。潜标与水面浮标由通信电缆连接,控制信息与数据信息可双向传输。浮标体集成扩频通讯电台,主控制台站通过无线电台完成对浮标与潜标的远程控制。外海试验表明：系统无线电通信速率可达11Mbps,作用距离15km,可在海上持续稳定工作30天。整套浮标与潜标系统已在工程项目中得到实际应用。     

Method of measuring vibrational temperatures in thermodynamically nonequilibrium gas flows

A numerical calculation is made of the integral radiation of CO₂ molecules in the 2.7- and 4.3-m bands and of CO molecules in the 4.7-m band when the vibrational temperatures significantly exceed the rotational and translational temperatures.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 3, pp. 411–419, March, 1980.     

Thermoelectric method of measuring velocity fluctuations in a gas stream

A method is described of measuring velocity fluctuations by using a thermocouple connected to a rapid response temperature-measuring instrument. It is shown that the method permits investigation of velocity fluctuations in a high-temperature gas stream.     

A new estimator for vector velocity estimation

A new estimator for determining the two-dimensional velocity vector using a pulsed ultrasound field is derived. The estimator uses a transversely modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new estimator automatically compensates for the axial velocity when determining the transverse velocity. The estimation is optimized by using a lag different from one in the estimation process, and noise artifacts are reduced by averaging RF samples. Further, compensation for the axial velocity can be introduced, and the velocity estimation is done at a fixed depth in tissue to reduce the influence of a spatial velocity spread. Examples for different velocity vectors and field conditions are shown using both simple and more complex field simulations. A relative accuracy of 10.1% is obtained for the transverse velocity estimates for a parabolic velocity profile for flow transverse to the ultrasound beam and a SNR of 20 dB using 20 pulse-echo lines. The overall bias in the estimates was -4.3%     

组合热膜探头在气体流速测量中的应用

介绍了一种用于测量气体流速的组合热膜探头,并对组合热膜探头的温度特性以及温度补偿性能进行了实验研究.实验结果表明,组合热膜探头在微小流速测量中具有较高的灵敏度,可以弥补毕托管在低速情况下测量误差较大的缺陷,且具有较好的一致性。     

Simultaneous PIV/OH-PLIF, Rayleigh thermometry/OH-PLIF and stereo PIV measurements in a low-swirl flame

The diagnostic techniques for simultaneous velocity and relative OH distribution, simultaneous temperature and relative OH distribution, and three component velocity mapping are described. The data extracted from the measurements include statistical moments for inflow fluid dynamics, temperature, conditional velocities, and scalar flux. The work is a first step in the development of a detailed large eddy simulation (LES) validation database for a turbulent, premixed flame. The low-swirl burner used in this investigation has many of the necessary attributes for LES model validation, including a simplified interior geometry; it operates well into the thin reaction zone for turbulent premixed flames, and flame stabilization is based entirely on the flow field and not on hardware or pilot flames.     

Metrological support system for means of measuring gas volume

A brief classification is given of gaseous injection-valve types, basic parameters, and metrological specifications. The general forms of the commonest working samplers are given. The state test scheme for means of measuring gas volumes with such devices is considered. Translated from Izmeritel'naya Tekhnika, No. 2, pp. 63–65, February, 1997.