Flow field diagnostics by spectrally filtered Rayleigh scattering

1990 ◽  
Author(s):  
Joseph Forkey ◽  
Walter R. Lempert ◽  
Richard B. Miles
Keyword(s):  
Flow Field ◽  
Rayleigh Scattering

Multi-Point Velocity Measurement of Gas Flow Field Based on Detecting the Doppler Frequency Shift of Molecular Rayleigh Scattering

2015 ◽  
Vol 42 (10) ◽  
pp. 1015002
Author(s):  
王晟 Wang Sheng ◽  
邵珺 Shao Jun ◽  
李国华 Li Guohua ◽  
赵新艳 Zhao Xinyan ◽  
胡志云 Hu Zhiyun ◽  
...  
Keyword(s):  
Flow Field ◽  
Frequency Shift ◽  
Velocity Measurement ◽  
Gas Flow ◽  
Rayleigh Scattering ◽  
Doppler Frequency ◽  
Doppler Frequency Shift ◽  
Point Velocity ◽  
Gas Flow Field

Assessment of Distributed Fiber Optic Sensors for Flow Field Temperature Mapping

2014 ◽  
Author(s):  
Steve Lomperski ◽  
Craig Gerardi
Keyword(s):  
Flow Field ◽  
Rayleigh Scattering ◽  
Fiber Optic ◽  
Imaging Techniques ◽  
Fiber Optic Sensors ◽  
Low Noise ◽  
Flow Induced Vibration ◽  
Thermal Mixing ◽  
Distributed Temperature Sensor ◽  
Data Density

Distributed fiber optic temperature sensing based on Rayleigh scattering is a relatively new technique offering data density unachievable with point sensors such as thermocouples and RTDs. Thousands of temperature measurements can be generated by a single fiber optic cable suspended within a flow field. And unlike imaging techniques such as laser induced fluorescence, fiber optic sensors are suitable for applications involving opaque fluids. But verifying measurement accuracy along a distributed temperature sensor (DTS) can be problematic. Unlike traditional sensors such as thermocouples, DTS calibration shifts can accompany sensor handling or movement because they respond to strain as well as temperature. This paper describes an assessment of a Rayleigh scattering-based sensing system used to measure air temperature within a 1 × 1 × 1.7 m tank used for thermal mixing experiments. Two 40 m-long DTSs were strung across the tank midplane at 16 levels. Stability in stagnant air was examined over seven days and found to be generally better than ± 0.5°C with local regions of drift up to 1.5°C. DTSs were also tested in isothermal flow to assess signal degradation associated with flow-induced vibration. Noise increased with flow velocity, inducing data loss that grew with distance along the fiber. Despite data losses >50% in high noise regions, mean temperatures after simple filtering agreed with low noise regions to within ∼4°C.

The application of laser-induced Rayleigh light scattering to the study of turbulent mixing

1984 ◽  
Vol 141 ◽  
pp. 391-429 ◽  
Author(s):  
William M. Pitts ◽  
Takashi Kashiwagi
Keyword(s):  
Light Scattering ◽  
Flow Field ◽  
Turbulent Flow ◽  
Rayleigh Scattering ◽  
Measurement Techniques ◽  
Experimental System ◽  
Digital Data ◽  
Rayleigh Light Scattering ◽  
Binary Gas Mixture ◽  
Rayleigh Light

This work describes the development and characterization of an experimental system employing laser-induced Rayleigh light scattering with digital data acquisition as a time-resolved quantitative concentration probe in the turbulent flow field of a binary gas mixture. Equations for the expected signal and noise levels are given. Estimates of these parameters for the experimental system used here are in satisfactory agreement with experiment. It is demonstrated that the laser Rayleigh-light-scattering technique provides measurements having high spatial and temporal resolution for various locations within the concentration flow field. Measurements at various positions in the flow field of an axisymmetric methane jet issuing into a slow flow of air are reported and, where possible, compared with appropriate literature results. The statistical properties of the turbulent concentration fluctuations are found to be in good agreement with other independent measurements. Conditionally sampled measurements are also reported and shown to behave in the same manner as the limited number of similar measurements in the literature. The capability of calculating power spectra and correlation functions for the time behaviour of the methane concentration is also demonstrated. Raman and Rayleigh scattering techniques are compared as measurement techniques of scalar values in turbulent flow fields.

RAYLEIGH SCATTERING OF MÖSSBAUER RADIATION ON VAPOUR-QUENCHED Te

1979 ◽  
Vol 40 (C2) ◽  
pp. C2-140-C2-141 ◽  
Author(s):  
F. M. Wagner ◽  
F. J. Litterst ◽  
G. M. Kalvius
Keyword(s):  
Rayleigh Scattering

Numerical Study of the Combined Free-Forced Convection and Mass Transfer Flow Past a Vertical Porous Plate in a Porous Medium with Heat Generation and Thermal Diffusion

2006 ◽  
Vol 11 (4) ◽  
pp. 331-343 ◽  
Author(s):  
M. S. Alam ◽  
M. M. Rahman ◽  
M. A. Samad
Keyword(s):  
Mass Transfer ◽  
Flow Field ◽  
Differential Equations ◽  
Forced Convection ◽  
Heat Generation ◽  
Numerical Study ◽  
Porous Plate ◽  
Integration Scheme ◽  
Suction Parameter ◽  
Transfer Flow

The problem of combined free-forced convection and mass transfer flow over a vertical porous flat plate, in presence of heat generation and thermaldiffusion, is studied numerically. The non-linear partial differential equations and their boundary conditions, describing the problem under consideration, are transformed into a system of ordinary differential equations by using usual similarity transformations. This system is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. The effects of suction parameter, heat generation parameter and Soret number are examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The analysis of the obtained results showed that the flow field is significantly influenced by these parameters.

Sign in / Sign up

Export Citation Format

Share Document