Gas Temperature Measurements Research Articles

Ultra-sensitive gas pressure and temperature sensor based on self-forming film technique and vernier effect

In this paper, an ultra-sensitive gas pressure and temperature sensor based on vernier effect is presented. It consists of a single mode fiber (SMF) and hollow cylindrical waveguides (HCW). Through the self-forming film technique, a gelatin film is manufactured at the air core of HCW, and the thickness of the gelatin film manufactured by this technique is only 3.16 μm. The vernier spectrum is formed by the superposition of the spectra of the air cavity (AC) and the mixing cavity. The mixing cavity is composed of AC and gelatin cavity (GC). The thin gelatin film makes the optical path difference between the AC and the mixing cavity smaller, which is beneficial to increase the vernier magnification factor. When the gas pressure changes, the gelatin film will deform abnormally. This abnormally deformation squeezes the film, causing the cavity length of the air cavity to become longer. The experimental results show that the sensor exhibits a high gas pressure sensitivity of 788.22 nm/MPa, and the temperature sensitivity is 0.39 nm/℃. The proposed sensor enables simultaneous measurement of gas pressure and temperature. It also processes the advantages of compact size, low cost, and strong mechanical strength, which makes it suitable for aerospace, Biomedical and Natural gas detection.

Experimental investigation, modeling and in-situ monitoring of a gas-driven absorption heat pump in Belgium

This work describes the methodology used to realize a performance analysis of an ammonia-water condensing gas absorption heat pump. This heat pump shows a nominal heating output of 18,9 kW for an outdoor temperature of 7 °C and a delivery temperature of 35 °C, and it is designed for domestic hot water and heating production. The experimental results obtained in the laboratory are contrasted with those obtained from the monitoring of two residential facilities in the northern part of Belgium. Experimental tests were carried out in a climatic chamber to emulate different outdoor climatic conditions based on a combination of the EN 12309 requirements and typical Belgium weather data. Measurements of gas consumption, electrical consumption, water flows, and temperatures were collected to compute performance indicators. On the other hand, the monitoring data was analyzed and contrasted with the experimental results to evaluate the field systems’ performance; the problems found and modifications made are described and discussed. The results show that the performance of the systems is highly dependent on the coupling with other appliances, on the operating conditions and control of the system, resulting in penalties that can be considerable depending on the configuration used. An empirical model calibrated with experimental data is proposed, as well as a penalization factor calibrated with the monitoring data. The results presented evidence the differences found between the studied facilities, highlighting the main role of proper installation and control not to diminish the main performance indicators.

Determination of Time Constant of Temperature Sensors and its Application in Aero Gas Turbine Engines

Temperature sensors are widely used in aero gas turbine engines for measurement of air and gas temperature at various locations starting from inlet of fan to exhaust gas from the nozzle. Thermocouples are one of the most widely used sensors for the above purpose. Time constant of thermocouple is a key parameter in the selection of sensor for a particular application. Even though time constant is available for standard stand alone thermocouple configurations, it varies widely based on many physical parameters and inlet flow conditions inside a gas turbine engine. Experimental determination of time constant of stand alone thermocouples with step input is carried out for various thermocouple configurations and a Fibre Bragg Grating sensor using a dry block calibrator with hot air as medium. Two different methods are used to determine the time constant of thermocouple sensors. Further determination of time constant of thermocouple assembled in a rake and tested in real time situation in aero gas turbine engine is carried out. A comparative study reveals that many parameters are involved which influence the value of time constant under different input conditions. Finally the selection of sensors is carried out based on the measurement requirements.

Composite Fabry-Perot interferometric gas pressure and temperature sensor utilizing four hole fiber with sensitivity boosted by high-order harmonic Vernier effect.

It is an enormous challenge for optical fiber sensors to intuitively achieve the simultaneous measurement of both gas pressure and temperature with high sensitivity. To address this challenge, the Fabry-Perot interferometer (FPI) based on high-order harmonic Vernier effect is combined with the fiber Bragg grating (FBG). A novel fiber sensor built with a cascaded FPI and an FBG for the simultaneous measurement of gas pressure and temperature is designed and experimentally investigated by virtue of the temperature sensing property of FBG and its independence on gas pressure-induced refractive index change, where a high-order harmonic Vernier effect was utilized to boost the gas pressure sensitivity of the sensor. As gas pressure increases from 0 to 1 MPa, the internal envelope of composite FBG and FPI based 10-order harmonic Vernier effect exhibits redshift with maximal sensitivities of 146.64 nm/MPa and a high magnification factor of 43. FBG is insensitive to gas pressure change, whereas, the spectral response of the internal envelope 10-order harmonic Vernier effect and FBG monotonously move and undergo blueshift and redshift as the temperature increases from 30 °C to 120 °C with maximal sensitivities of -0.48 and 0.011 nm/°C, respectively. Therefore, the distinct sensitivities of FBG and FPI to gas pressure and temperature result in extraction of both gas pressure and temperature information simultaneously by constructing measurement matrixes.

Influence of thermocouple angles and wire distance on temperature measurement

When a thermocouple is used to measure gas temperature, the measured temperature, i.e., the thermocouple bead temperature, is not equal to the gas temperature. The bead temperature results from the bead energy balance. The positioning angles such as the pitch angle and the roll angle and the wire distance of the thermocouple will influence the convection heat transfer of the thermocouple, causing the bead temperature variation. Two S type thermocouples are used to measure the temperature of the H2/air Hencken flame with the equivalence ratio 0.7. The maximum measurement temperature changes are 52 K and 79 K for the pitch angle variation and the roll angle variation, respectively. CFD simulations are carried out to simulate the experimental phenomena. The differences between the simulated and measured bead temperatures are less than 20.4 K. With 90° roll angle, the bead temperature increases first then decreases with the pitch angle. With 90° pitch angle, the bead temperature increases first then decreases with the roll angle. With 0° pitch angle, the bead temperature increases monotonically with the wire distance. The background physical mechanisms of the phenomena are analyzed with the detailed CFD results.

Generating a virtual physical model through measurement data and reverse engineering: Applying a performance prediction model for an industrial gas turbine during start-up

The gas turbine virtual physical model can be applied to various fields such as performance optimization, diagnostics, and prognostics. For this purpose, it is important to increase the accuracy of the physical model. However, in order to generate such a model, the design information and off-design performance characteristics of its components are required, yet it is difficult to obtain this information because manufacturers do not generally release it. This study proposes a method for the generation of a virtual physical model to predict gas turbine system performance through reverse engineering, based on operational data but without information on component performance or design information; its effectiveness is discussed. There have been many studies to correct an initial gas turbine’s physical model using operational data. In the existing studies, detailed component performance and design information was required, to generate an initial physical model. It is normally difficult to obtain component performances and design information. Therefore, a method is proposed to generate a physical model at a reference point, using operating data and assumed information, and to create a final physical model through component performance map correction. An initial physical model is constructed based on the information and performance characteristics used for general gas turbine components, not design information of the target engine. The component blocks consisting of the gas turbine are simplified by combining them at each region. In addition, a method of estimating the moment of inertia of a gas turbine’s rotating parts, using operating data, was proposed. The target engine is a single-shaft industrial gas turbine consisting of a compressor, combustor, and turbine. A virtual physical model was created using one of the three datasets measured in the start-up operation; the accuracy of the generated model was verified using the other two datasets. Shaft speed, fuel mass flow rate, compressor exit temperature, compressor total pressure ratio, and exhaust gas temperature measurement data were used. As a result, it was confirmed that, for both the data used to generate the model and the data that were not, the model predicted the measured variables well. It is expected that the proposed method can be used to create a virtual physical model for use in operation optimization and diagnostics from the operator's point of view, where it is difficult to obtain component performance and design information.

Deep Synoptic Array Science: Two Fast Radio Burst Sources in Massive Galaxy Clusters

The hot gas that constitutes the intracluster medium (ICM) has been studied at X-ray and millimeter/submillimeter wavelengths (Sunyaev–Zel’dovich effect) for decades. Fast radio bursts (FRBs) offer an additional method of directly measuring the ICM and gas surrounding clusters via observables such as dispersion measure (DM) and Faraday rotation measure. We report the discovery of two FRB sources detected with the Deep Synoptic Array whose host galaxies belong to massive galaxy clusters. In both cases, the FRBs exhibit excess extragalactic DM, some of which likely originate in the ICM of their respective clusters. FRB 20220914A resides in the galaxy cluster A2310 at z = 0.1125 with a projected offset from the cluster center of 520 ± 50 kpc. The host of a second source, FRB 20220509G, is an elliptical galaxy at z = 0.0894 that belongs to the galaxy cluster A2311 at the projected offset of 870 ± 50 kpc. These sources represent the first time an FRB has been localized to a galaxy cluster. We combine our FRB data with archival X-ray, Sunyaev–Zel'dovich (SZ), and optical observations of these clusters in order to infer properties of the ICM, including a measurement of gas temperature from DM and y SZ of 0.8–3.9 keV. We then compare our results to massive cluster halos from the IllustrisTNG simulation. Finally, we describe how large samples of localized FRBs from future surveys will constrain the ICM, particularly beyond the virial radius of clusters.

Thin-Wire Thermocouple Design for Exhaust Gas Temperature Pulse Measurements in Internal Combustion Engines

<div>Accurate exhaust gas temperature (EGT) measurements are vital in the design and development process of internal combustion engines (ICEs). The unsteady ICE exhaust flow and thermal inertia of commonly used sheathed thermocouples and resistance thermometers require high bandwidth EGT pulse measurements for accurate cycle-resolved and mean EGTs. The EGT pulse measurement challenge is typically addressed using exposed thin-wire resistance thermometers or thermocouples. The sensor robustness to response tradeoff limits ICE tests to short durations over a few exhaust conditions. Larger diameter multiwire thermocouples using response compensation potentially overcomes the tradeoff. However, the literature commonly adopts weaker slack wire designs despite indications of coated weld taut wires being robust. This study experimentally evaluates the thin-wire thermocouple design placed in the exhaust of a heavy-duty diesel engine over wide-ranging exhaust conditions for improving both sensor robustness and accuracy of the measured EGT. The assessed design parameters included the wire diameter (51 μm to 254 μm), the exposed wire length, and the wires placed slack or taut with coated weld faces. All taut wires with ceramic-coated weld faces endured over 3 h of engine operation, while similar diameter slack wires (51 μm and 76 μm) were sensitive to the exhaust condition and exposed wire length. Reducing the wire diameter from 76 μm to 51 μm significantly impacted response improvements as evidenced at certain test conditions by a peak-peak EGT increase of 92 °C, a mean EGT drop of 26 °C, and a doubling of the sensitivity of mean EGT cycle-to-cycle variations to ±12 °C. Increasing the exposed wire length showed less significant response improvements. The Type-K thin-wire thermocouples showed negligible drift, thereby indicating the possibility of using smaller and longer wires built taut with coated weld faces for improved accuracy of EGT measurements in ICEs.</div>

Compact Harmonic Vernier Sensor Based on an In-Fiber FPI with Three Reflector System for Simultaneous Gas Pressure and Temperature Measurement.

In this work, we proposed a sensitivity-enhanced temperature sensor, a compact harmonic Vernier sensor based on an in-fiber Fabry-Perot Interferometer (FPI), with three reflective interfaces for the measurement of gas temperature and pressure. FPI consists of air and silica cavities formulated by single-mode optical fiber (SMF) and several short hollow core fiber segments. One of the cavity lengths is deliberately made larger to excite several harmonics of the Vernier effect that have different sensitivity magnifications to the gas pressure and temperature. The spectral curve could be demodulated using a digital bandpass filter to extract the interference spectrum according to the spatial frequencies of resonance cavities. The findings indicate that the material and structural properties of the resonance cavities have an impact on the respective temperature sensitivity and pressure sensitivity. The measured pressure sensitivity and temperature sensitivity of the proposed sensor are 114 nm/MPa and 176 pm/°C, respectively. Therefore, the proposed sensor combines ease of fabrication and high sensitivity, making it great potential for practical sensing measurements.

On the gas heating effect of helium atmospheric pressure plasma jet

Plasma medicine is an emerging research field which has been driven by the development of plasma sources suitable to generate low temperature plasmas. In many cases, such devices can operate without a gas flow, producing a plasma discharge from the ambient air. However, the most common case is the use of a working gas at a given flow rate to produce a plasma jet. Helium (He) is one of the gases commonly used as the carrier gas to generate cold atmospheric pressure plasma jets (CAPPJs) due mainly to the easiness to ignite a gas discharge with it. However, in this work it was observed that most of the heating of a He CAPPJ can come just from the expansion of the He gas. This was found through measurements of gas temperature (T gas ), using fiber optic temperature (FOT) sensors, and thermal output, using both FOT and infrared imaging with the He flow impinging on a copper (Cu) plate. Such findings were achieved through comparisons of T gas and the temperature on the Cu (T Cu ) plate in the conditions with and without discharge ignition, as well as comparing T gas in the free gas/jet mode with and without discharge ignition. It was verified that the T gas values increased as the distance from the gas outlet was enlarged, especially at low He flow rates, even without discharge ignition. Despite the temperature increase with distance, it is possible to produce plasma jets with temperatures lower than 40 °C at low He flow rates.

Steady-state error estimation and calibration of a shielded total temperature probe for turbomachinery

Accurate measurement of the total gas temperature plays a vital role in the performance research of turbomachinery. The total temperature thermocouple (TC) used in the measurement often needs to be specially designed and calibrated. In the past, the calibration was usually completed by a complex and highly costly experiment. The present work developed a new shielded total temperature probe (NTTP) for relatively low-temperature gas measurement. Meantime, this new design's characteristics and different error sources are analyzed based on the Conjugate Heat Transfer (CHT) simulation method. The CHT results show that the thermal conduction error is kept at a small value in the range of Mach number from 0.2 to 0.6; The velocity error contributes more than 90% of the total error. Four standard temperature probes are selected for the comparison. The maximum measurement error is 1.13 K, which is 331.62%, 119.4%, 61.6% and 59.5% lower than the standard type-A, B, C and D, respectively. Moreover, the detailed flow field and the influence of TC junction position on measurement accuracy are discussed. With the increases of the junction away from the supporting, the total measurement error of the NTTP increases first and then decreases. To vindicate the applicability of the proposed design, the measurement error of the NTTP is verified by a new experimental method with the relatively static fluid as the gas flow source. The testing results show that when the inflow's Mach number is 0.52, the measurement error of the NTTP is about 40% lower than that of the type-C total temperature probe.

Combustion Characteristics of Natural Gas/Air Flat Premixed Laminar Flames in a Developed Matrix Burner

The natural gas flat flame characteristics are experimentally and numerically investigated under different equivalence ratios. A matrix burner is designed so that the natural gas-air mixture from the matrix burner makes up the flat flame. The combustion characteristics, such as the flame lift, the flame thickness, the gas temperatures, and the species concentration, are measured. The measured species concentrations are compared to the computed concentrations using different chemical kinetic mechanisms. The work was carried out at atmospheric pressure and room temperature at different equivalence ratios of 0.6, 0.8, 1, 1.2, and 1.4. A close agreement occurs between the experimental and the simulation results at lean and stoichiometric conditions with a mean absolute error value ranging from 0.9:3. At stoichiometric conditions, the maximum measured gas temperature, the flame thickness, and the minimum flame lift-off all coincide with the maximum simulated mole fractions of CO2 and NO. In addition, the centreline axial temperature is low just above the burner top (i.e., the flame lift region). However, those temperatures increase as the distance above the burner top increases.

Full-scale investigations of initial deposits formation in a cement plant co-fired with coal and SRF

This work investigates the initial (short-term) deposit formation in a cement calciner co-fired with coal and SRF (Solid Recovered Fuel). The main objective was to evaluate and compare the tendencies of deposit formation (i.e. material deposition rate and composition) at different locations (heights) in the calciner system, during different operation conditions. A steel probe was used to collect initial deposits from four different sampling locations: i) in the kiln riser (two sampling locations), ii) in the mid calciner, and, iii) at the outlet from the bottom stage preheater cyclone (C5). After an exposure time of the probe between 1 and 20 min, the collected deposit samples were weighted and characterized by SEM-EDX, ICP-OES/IC, and XRD. Plant operation data, measured gas temperatures, as well as gas phase composition data (i.e. KCl(g) and SO2(g)), supported the evaluation of deposit formation. Due to high particle flux (up to approx. 61,000 kg/(m2·h) in the riser duct), the average net deposit formation rate was around 500 kg/(m2·h) for 1 min exposure time, decreasing to <100 kg/(m2·h) for exposure times ≥4 min (due to spontaneous shedding and erosion). The deposits contained primarily five crystalline phases (CaO, CaCO3, Ca(OH)2, KCl, and SiO2), which is in general consistence with the composition of the admitted preheated raw meal (C4 meal) at measurement locations, with a slight enrichment in KCl, suggesting some condensation of volatile elements from the high-temperature gas phase on the surface of the somewhat colder deposit particles. Further, the deposit samples obtained in the kiln riser had a higher degree of calcination (higher proportion of CaO as compared to CaCO3) as compared to the admitted C4 meal, suggesting carry-over of dust from the kiln feed pipe, or fast calcination of the riser meal due to high temperature.The collected short-term deposits differ significantly from long-term (mature) deposits, which have previously been collected from the site, in terms of chemical and physical properties. Compared to short-term deposits, which had a content of KCl in the range of approx. 3–5 wt%, the content of KCl in the mature deposits increased substantially from around 2 wt% in samples from the kiln riser area to a level of >20 wt% in the calciner and C5 cyclone area, implying significant accumulation of KCl caused by volatile circulation and condensation from the hot gas on surfaces with locally lower temperatures. The most prevalent crystalline phases in the mature deposits were KCl, CaCO3, and the mineral spurrite (Ca5(SiO4)2CO3). The presence of spurrite implied that SiO2 reacts with CaCO3, or with CaO and gaseous CO2, to form spurrite during long-term deposit build-up and maturation.Overall, the results from this work suggest that the short-term deposit formation in the cement calciner is dominated by impaction. The composition of the short-term deposits is quite similar to the composition of the entrained C4 meal particles; while the build-up of mature deposits is influenced greatly by local temperature gradients and long-term fluctuations. I.e. in zones with locally lower temperatures, such as cold area of calciner walls (< ∼850 °C), heterogeneous condensation and/or thermophoresis of KCl from the high-temperature flue gas is facilitated.

Combustion Variability Monitoring in Engines Using High-Speed Exhaust Temperature and Pressure Measurements

AbstractThe diagnostic merits of high-speed (HS) exhaust gas temperature and pressure measurements for indexing engine stability and identifying abnormal combustion cycles are explored through experimental investigations on a low speed, single-cylinder engine. Exhaust temperature and pressure are measured using a fine wire 50 μm thermocouple and a piezoresistive pressure transducer, respectively. Synchronously recorded cylinder pressure data is used to continuously index combustion variations, and then anomalous combustion event detection and engine stability monitoring are attempted using HS exhaust temperature and pressure measurements. Two types of abnormal combustion cycles, namely, misfiring and overload cycles are used to typify low and high intensity anomalous combustion cycles, respectively. The results demonstrate that if suitable cyclic exhaust pressure and temperature metrics are used, anomalous combustion cycles can be identified, and overall combustion variability levels can be indexed. The comparative diagnostic performance of HS measured exhaust pressure and temperature and slow speed measured exhaust temperature are also discussed. A thermodynamic simulation of the engine and the HS thermocouple is used to provide theoretical support for the discussion by comparing measured and simulated “actual” exhaust temperature and identifying the flow, heat transfer, and thermodynamic influences that act as limits to the thermocouple's dynamic performance.

Simultaneous measurement of carbon emission and gas temperature via laser-induced breakdown spectroscopy coupled with machine learning.

A method, which can accurately measure carbon emission and gas temperature simultaneously in real-time from a laser-induced breakdown spectrum (LIBS) via machine learning, is proposed in this study. In typical, peak intensity ratios had been used to map species concentrations prior to plasma formation, after removing the broadband continuum of the spectrum; however, the dependence of these peak intensity ratios on the concentration changes with the change in gas density. Therefore, considering the fact that the strength and shape of this broadband continuum is a function of the gas density for a given optical setup, we attempted to collect a spectrum by shortening the time delay after the laser fire, such that the spectrum can contain some of the broadband continuum. Since the analytical quantification of this broadband continuum is not trivial, we employed a machine learning approach to acquire a model that simultaneously predicts the gas temperature and CO2 concentration. The predictive performance of the model trained with spectra that contain the broadband continuum was much better than that without it; the gradient-weighted regression activation mapping (Grad-RAM) analysis revealed that the model utilizes the broadband spectrum for temperature prediction and correction of changes in peak intensity due to temperature changes in the concentration prediction process.

Periodic gas temperature measurement as an inverse heat transfer problem, utilization of the Particle Filter algorithm and mechanistic models

In many engineering applications one can find periodically variable gas temperatures. Possible examples include the temperature inside the cylinders of Stirling Engines and other reciprocating machines. New methods are proposed and evaluated for the measurement of periodically varying temperature by thermocouples. A Computational Fluid Dynamics model is created to assess the method viability and efficacy in a realistic setting while avoiding measurement errors. The first method is based on matrix analysis, the two others on the particle filter algorithm used to estimate either the heat transfer coefficients with the additional use of other flow information, or to estimate the thermocouple constants without said information. It is shown that the matrix method is sufficient for cases with constant velocities. For variable velocities, the PF algorithm shows promising results as based on measurements generated from the numerical simulation.

Flame, Combustion and Explosion Thermometry

Flame is a natural phenomenon and is a basic element of any combustion process. The majority of flames consist of a gas; there is, however, a small amount of ionisation occurring in the flame. Despite the increased focus on combustion-free energy production such as wind, air and water power, and the refocus on nuclear energy now considered to be carbon-free, nonetheless combustion will remain, for the next few decades, the major energy and heat production route worldwide. Apart from carbon dioxide, which is commonly considered to be the major pollutant, there are other gases like nitric oxide and nitrogen dioxide which, although found in significantly lower amounts in the exhaust gases from combustion units, still present a large environmental impact and are a concern. There are however well-established technologies for removing combustion products from the exhaust gas, and the combustion process can in general be made CO2 and environmentally neutral. Combustion optimisation is a route for further reduction of undesirable byproducts, fuel consumption minimisation and finally an overall energy and heat production enhancement. The key parameter in any combustion process is reliable flame and (post-) combustion gas temperature measurement and control. Various combustion environments such as waste incineration, internal combustion engines or solids explosions cause the appearance of various optical emission features in different spectral ranges not accessible to the human eye. A combination of modern and newly developed fast spectral optical techniques with extensive theoretical developments in spectral and heat radiative transfer modelling allows us to obtain detailed snapshots of what is happening in the combustion process. That also gives a possibility to establish a direct link to the industrial process control and pollutant emission reduction. In this article some examples of in situ flame and gas temperature measurements in various combustion environments and advanced spectral modelling are given and perspectives for further commercial instrumentation developments are discussed.

Gas temperature measurement by atomic line broadening using the LIBS technique

The ambient temperature affects the electron density in the laser-induced plasma, which is reflected as changes in the atomic spectral linewidths. A thermometry technique for the gas flow field under constant pressure is proposed.

Exergy Analysis of Organic Rankine Cycles with Zeotropic Working Fluids

Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines. Instead of wasting the exhaust stream of an energy conversion system into the environment, its residual energy content can be usefully recovered, for example in Organic Rankine Cycles (ORC). This technology has been largely consolidated in stationary power plants but not yet for mobile applications, such as road transport, due to the limitations in the layout and to the constraints on the size and weight of the ORC system. An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated. The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation. The waste thermal power has been considered as heat input for the ORC plant simulation. A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance. The exergy analysis of the ORC was performed comparing different working fluids: R601, R1233zd(E) and two zeotropic blends of the two organic pure fluids. The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.

Bias-Immune Absorption Spectrum Extraction by Downsampling the Wavelength Modulation Laser Signal for Precise Measurement of Dynamic Gas Temperature

Precise and bias-immune absorption spectrum was directly extracted from wavelength-modulated intensities for dynamic gas temperatures by a proposed novel downsampling scheme. Absorbed wavelength-modulated laser intensity generated multiple direct absorption profiles by downsampling at equal phases in each modulation cycle. The number of achieved profiles equals to that of sampled intensities in each wavelength modulation cycle. All these profiles are employed to remove intensity biases from thermal radiations and obtain an entire absorption spectrum of target gases. A water-based thermostat was used to evaluate the noise reduction of the proposed method in controlled noisy cases. Deviations of achieved gas temperatures are less than 4°C, and precision is quantitated by SNR values that achieved by the proposed method are respectively 15 dB and 5 dB higher than those of direct absorption spectroscopy and wavelength modulation spectroscopy methods. Dynamic temperatures measured by the proposed method are used to evaluate temporal variations of an acoustically excited flame. It identified the sinusoidal temperature variation, and its harmonic strength at the target frequency is 1.5 times stronger than that of the direct absorption spectrum method in noisy cases, e.g. SNR from 40 to 60 dB. The intensity bias from the thermal radiation is also derived by the proposed method, and the bias value agrees well with that of the reference detector for radiative variations of a correlation coefficient of 0.98. Both simulated and experiment results verified the robust performance of the proposed method for flame temperatures with strong thermal radiation and noises.