Temperature measurement by holographic interferometry in liquids (original) (raw)
Related papers
Fuel, 2007
This investigation developed a systematic method to measure the temperatures and the mass concentrations of local species in a nonpremixed ethylene-air flame using the holographic interferometry (HI) technique. A nearly linear state relationship between the Gladstone-Dale constant and the mixture fraction was deduced. Normalized state relationships between the refractive index and the mixture fraction were established from detailed combustion simulations for the NPFs. The maximum error of temperature caused by the assumption of composition of air was reduced from 48.84% to under 1.6% for the NPFs using the systematic method. The method can overcome the difficulty that the concentrations of local species must be known when measuring the temperature by HI for NPFs.
Temperature measurement by holographic interferometry in liquids for transient flame spread
1994
This investigation developed a systematic method to measure the temperatures and the mass concentrations of local species in a nonpremixed ethylene-air flame using the holographic interferometry (HI) technique. A nearly linear state relationship between the Gladstone-Dale constant and the mixture fraction was deduced. Normalized state relationships between the refractive index and the mixture fraction were established from detailed combustion simulations for the NPFs. The maximum error of temperature caused by the assumption of composition of air was reduced from 48.84% to under 1.6% for the NPFs using the systematic method. The method can overcome the difficulty that the concentrations of local species must be known when measuring the temperature by HI for NPFs.
Applied Optics, 2006
What is believed to be a new technique that allows for the simultaneous measurement of 2D temperature and chemical species concentration profiles with high spatial resolution and fast time response was developed and tested successfully by measuring a thin layer of fuel vapor created over a volatile fuel surface. Normal propanol was placed in an open-top rectangular container, and n-propanol fuel vapor was formed over the propanol surface in a quiescent laboratory environment. An IR beam with a wavelength of 8 -13 m emitted from a heated plate and a He-Ne laser beam with a wavelength of 632 nm were combined and passed through the n-propanol vapor layer, and both beams were absorbed by the vapor layer. The absorption of the IR beam was recorded by an IR camera, and the He-Ne laser was used to form a holographic interferogram. Two-dimensional temperature and propanol vapor concentration profiles were, respectively, determined by the IR absorption and the fringe pattern associated with the holographic interferogram. This new measurement technique is a significant improvement over the dual wavelength holographic interferometry that has been used previously to measure temperature and fuel concentration, and it is ready for application under different types of fire and flame conditions.
Digital holographic interferometry for measurement of temperature in axisymmetric flames
Applied Optics, 2012
In this paper, experimental investigations and analysis is presented to measure the temperature and temperature profile of gaseous flames using lensless Fourier transform digital holographic interferometry. The evaluations of the experimental results give the accuracy, sensitivity, spatial resolution, and range of measurements to be well within the experimental limits. Details of the experimental results and analysis are presented.
SAE Technical Papers, 2004
Temperature distribution as the flame propagated and contacted to the wall of the combustion chamber was measured by real-time holographic interference method, which mainly consisted of an argon-ion laser and a highspeed video camera. The experiment was done with a constant volume chamber and propane-air mixture with several kinds of quivalence ratios. From the experimental results, it can be found that the temperature distribution outside the zone from the surface of the combustion chamber to 0.1mm distance could be measured by counting the number of the interference fringes, but couldn’t within this zone because of lacking in the resolution of the used optical system. The experimental results show that the temperature distribution when the heat flux on the wall increases rapidly and when the heat flux shows the maximum value are quite different by the equivalence ratio. Therefore, the temperature distribution when the heat flux shows the maximum is related with the lower temperature of ignition temperature.
Combustion and flame, 2000
The local flow temperature is a key consequence of combustion and must, therefore, be accurately measured. Holographic interferometry can be employed to accurately determine the refractive index in flames and, thereafter, to infer the temperature distribution. This investigation focuses on the utility of laser interferometric holography as a tool to measure the temperature of two-dimensional partially premixed flames (PPFs). Methane-air PPFs are established on a rectangular Wolfhard-Parker slot burner. These flames contain two reaction zones, one in an outer nonpremixed region and the other in an inner rich-premixed region. We examine flame structure effects (that produce a varying composition in the flame) on the local refractive index and show that a relation that contains relatively minor errors, which depend upon the rich-side equivalence ratio, can model the refractive index in PPFs. This is the first investigation to discuss the effects of a realistically varying composition due to combustion on the refractive index distribution in flames. The maximum error in the temperature is 6 -34% when the rich-side equivalence ratio lies in the range 1.5-ϱ, while the corresponding average error is 2.4 -12.3%. Relatively large discrepancies arise in the case of nonpremixed flames. We discuss the experimental configurations required to reconstruct clear interferometric fringe patterns. Image plane holography is employed because it offers two advantages: (1) the holograms can be read with white light, and (2) the fringe count may be considered to occur in a straight line as though no refraction had occurred. We confirm the inefficacy of using thermocouples as a measurement tool in two-dimensional PPFs. Questions related to the beam path length are resolved. The portion of the flame-beam interference length that lies between the high and low temperatures is accounted for by assuming a uniform composition and by introducing a density weighting function. Thereafter, we examine the holographic fringe patterns, discuss the discrepancies that arise in the interpreted temperatures as the PPF equivalence ratio is varied, and present the inferred temperature distributions. The temperature distribution is found to correlate with the heat release in the inner rich premixed and outer nonpremixed reaction zones. Large temperature gradients exist in the inner premixed reaction zone, whereas the outer nonpremixed region contains smaller gradients, since it is transport limited. The spatial temperature resolution required to resolve the higher gradients is Ϸ400 K mm Ϫ1 .
OSA Imaging and Applied Optics Congress 2021 (3D, COSI, DH, ISA, pcAOP), 2021
Measuremellt of accurate spa/wi distribution of temperature and temperclfllre flltclIlarion ill aflame is importam to study the cO/llbu~•tiol/ process ill detail. IlIlhis paper first we have presented nreasuremellt of temperarure profile of a gaseous fla/llf! of {I /Wodimellsional slot burner. The erm,.~, due to halu effect in the measuremellts oltemperature are minimized by correcting the width ofthe/rillges. Further single e).posure speckle photography is used to study temperarurej1uctlf(ltion illside thej1ame. The 3-D plot of temperature fluctuation for differem fuel flow rates of air alld aeety/elle at different vertical heights above the mouth of the bumer with distance from the one elld of the .burner is also presented.
Candle flame analysis by digital three-wavelength holographic interferometry
Fringe 2009, 2009
A digital three-color holographic interferometer was designed to analyze the variations in refractive index induced by a candle flame. Color holograms are generated and recorded with a three layer photodiode stack sensor allowing a simultaneous recording with a high spatial resolution. Phase maps are calculated using Fourier transform and spectral filtering is applied to eliminate parasitic diffraction orders. Then, the contribution along each color is obtained with the simultaneous three wavelength measurement. Results in the case of the candle flame are presented. Zero order fringe, meaning zero optical path difference, can be easily extracted from the experimental data, either by considering a modeled colored fringe pattern or the wrapped phases along the three wavelengths.
Optics and Lasers in Engineering, 2019
In this communication, the measurement of flame temperature and flame temperature instability in macro, microsized flames using digital holographic interferometer based on volume phase holographic optical element is experimentally demonstrated. Volume phase holographic optical element (grating) recorded on dichromatic gelatine is used as a beam splitter to design digital holographic interferometer. Volume phase holographic grating will split the incoming light beam into zero, + 1, − 1 orders. The two beams (zero order and + 1 order) can be made of equal intensities by slightly tilting the grating in the path of the beam. Volume phase holographic grating can be designed and fabricated to have high diffraction efficiency (≈90%) and remove stray light from the system reaching to the grating and will lower the coherent noise (speckle pattern). This will improve the contrast of interference fringes while recording the hologram and thus will provide better quality interferograms of temperature field. This type of system is expected to give more accurate measurements as noise due to the speckle pattern, and scattering will become almost negligible.