Visual and dynamic measurement of temperature fields by use of digital holographic interferometry

2013 ◽  
Author(s):  
Jianlin Zhao ◽  
Jianglei Di ◽  
Bingjing Wu ◽  
Jun Wang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Holographic Interferometry ◽  
Dynamic Measurement ◽  
Temperature Fields

The Possibility of Visualizing Temperature Fields Using Digital Holographic Interferometry

2013 ◽  
Vol 284-287 ◽  
pp. 988-995 ◽  
Author(s):  
Tomáš Vít ◽  
Vít Lédl ◽  
Roman Dolecek ◽  
Pavel Psota
Keyword(s):  
Holographic Interferometry ◽  
Rapid Change ◽  
Optical Methods ◽  
Temperature Fields ◽  
Constant Current ◽  
Special Technique ◽  
Limiting Factor ◽  
Measured Temperature ◽  
Hot Wire ◽  
First Results

The presented paper compares results of measured temperature fields achieved by digital holographic interferometry (DHI) and hot wire anemometry. It shows the possibility of using holographic interferometry for the visualization of temperature fields in periodically moving fluids. The measurement of temperature fields in moving fluids has many inherent difficulties. The usage of point temperature measurement methods, such as Constant Current Anemometry (CCA), is limited to frequencies up to 3000 Hz. This frequency should be the limiting factor for using CCA in fluids when a rapid change of temperature occurs. This shortcoming of CCA measurements could be overcome through the use of optical methods such as digital holographic interferometry. It is necessary to employ a special holographic setup with double sensitivity instead of the commonly used Mach-Zehnder type of holographic interferometer in order to attain parameters sufficient for the studied case. This setup is not as light-efficient as the Mach-Zehnder type but has double sensitivity. The special technique of acquiring and phase averaging the results from holographic interferometry is presented. The paper also shows the first results of an evaluated 3D temperature field.

scholarly journals Intensification of heat transfer between heat exchange surfaces at low RE values

2015 ◽  
Vol 36 (3) ◽  
pp. 331-344
Author(s):  
Jozef Cernecky ◽  
Zuzana Brodnianska ◽  
Jan Koniar
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Friction Coefficient ◽  
Holographic Interferometry ◽  
Temperature Fields ◽  
Pressure Losses ◽  
Interferometry Method ◽  
Transfer Parameters ◽  
Holographic Interferometry Method ◽  
Quantitative Evaluations

Abstract This contribution deals with the heat transfer parameters and pressure losses in heat exchange sets with six geometrical arrangements at low Re values (Re from 476 to 2926). Geometrical arrangements were characterised by the h/H ratio ranging from 0.2 to 1.0. The experiments used the holographic interferometry method in real time. This method enables visible and quantitative evaluations of images of temperature fields in the examined heat exchange. These images are used to determine the local and mean heat transfer parameters. The obtained data were used to determine the Colburn j-factor and the friction coefficient f. The measured values show that by using the profiled heat exchange surfaces and inserting regulating tubes, an intensification of heat transfer (increase of Num, and/or j) was achieved. However, pressure losses recorded a significant increase (increase of f).

The Effect of Heat Transfer Area Roughness on Heat Transfer Enhancement by Forced Convection

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Jozef Cernecky ◽  
Jan Koniar ◽  
Zuzana Brodnianska
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Forced Convection ◽  
Holographic Interferometry ◽  
Temperature Fields ◽  
Heat Transfer Area ◽  
Transfer Enhancement ◽  
Nusselt Numbers ◽  
Air Convection ◽  
Forced Air

The paper deals with the visualization of temperature fields in the vicinity of profiled heat transfer surfaces and a subsequent analysis of local values of Nusselt numbers by forced air convection in an experimental channel. Holographic interferometry was used for visualizing the temperature fields. Experiments were carried out at Re 462 up to 2338 at the distances between heat transfer surfaces of 0.025 m and 0.035 m. Temperature contours were determined from the obtained images of holographic interferograms of temperature fields and the local values of Nusselt numbers along the profiled surface for x/s = 0 up to x/s = 1.25 were calculated from them. A significant effect of the profiled surface on the local values of Nusselt numbers can be observed from the obtained results.

Sign in / Sign up

Export Citation Format

Share Document