Experimental Studies on Heat Release Rate in Chinese Kitchen Fires

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.

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Heat release rate shaping for optimal gross indicated efficiency in a heavy-duty RCCI engine fueled with E85 and diesel

Fuel ◽

10.1016/j.fuel.2020.119656 ◽

2021 ◽

Vol 288 ◽

pp. 119656

Author(s):

Robbert Willems ◽

Frank Willems ◽

Niels Deen ◽

Bart Somers

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Heavy Duty ◽

Rate Shaping

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Experimental and Simulation of Diesel Engine Fueled with Biodiesel with Variations in Heat Loss Model

Energies ◽

10.3390/en14061622 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1622

Author(s):

Daniel Romeo Kamta Legue ◽

Zacharie Merlin Ayissi ◽

Mahamat Hassane Babikir ◽

Marcel Obounou ◽

Henri Paul Ekobena Fouda

Keyword(s):

Heat Release ◽

Heat Loss ◽

Heat Release Rate ◽

Release Rate ◽

Diffusion Combustion ◽

Cylinder Wall ◽

Compression Ignition Engine ◽

Experimental Conditions ◽

Load Range ◽

Combustion Phase

This study presents an experimental investigation and thermodynamic 0D modeling of the combustion of a compression-ignition engine, fueled by an alternative fuel based on neem biodiesel (B100) as well as conventional diesel (D100). The study highlights the effects of the engine load at 50%, 75% and 100% and the influence of the heat loss models proposed by Woschni, Eichelberg and Hohenberg on the variation in the cylinder pressure. The study shows that the heat loss through the cylinder wall is more pronounced during diffusion combustion regardless of the nature of the fuels tested and the load range required. The cylinder pressures when using B100 estimated at 89 bars are relatively higher than when using D100, about 3.3% greater under the same experimental conditions. It is also observed that the problem of the high pressure associated with the use of biodiesels in engines can be solved by optimizing the ignition delay. The net heat release rate remains roughly the same when using D100 and B100 at 100% load. At low loads, the D100 heat release rate is higher than B100. The investigation shows how wall heat losses are more pronounced in the diffusion combustion phase, relative to the premix phase, by presenting variations in the curves.

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Detailed Derivations of Formulas for Heat Release Rate Calculations Revisited: A Pedagogical and Systematic Approach

Journal of Research of the National Institute of Standards and Technology ◽

10.6028/jres.124.016 ◽

2019 ◽

Vol 124 ◽

Author(s):

Jiann C. Yang

Keyword(s):

Oxygen Consumption ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Chemical Engineering ◽

Chemical Species ◽

Flow Process ◽

Generalized Framework ◽

Oxygen Consumption Calorimetry ◽

Engineering Practices

The derivations of the formulas for heat release rate calculations are revisited based on the oxygen consumption principle. A systematic, structured, and pedagogical approach to formulate the problem and derive the generalized formulas with fewer assumptions is used. The operation of oxygen consumption calorimetry is treated as a chemical flow process, the problem is formulated in matrix notation, and the associated material balances using the tie component concept commonly used in chemical engineering practices are solved. The derivation procedure described is intuitive and easy to follow. Inclusion of other chemical species in the measurements and calculations can be easily implemented using the generalized framework developed here.

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Flame dynamics and unsteady heat release rate of self-excited azimuthal modes in an annular combustor

Combustion and Flame ◽

10.1016/j.combustflame.2014.03.021 ◽

2014 ◽

Vol 161 (10) ◽

pp. 2565-2578 ◽

Cited By ~ 47

Author(s):

James R. Dawson ◽

Nicholas A. Worth

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Flame Dynamics ◽

Annular Combustor

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Optical Measurement of Local and Global Transfer Functions for Equivalence Ratio Fluctuations in a Turbulent Swirl Flame

Volume 1B: Combustion, Fuels and Emissions ◽

10.1115/gt2013-95649 ◽

2013 ◽

Cited By ~ 1

Author(s):

Bernhard C. Bobusch ◽

Bernhard Ćosić ◽

Jonas P. Moeck ◽

Christian Oliver Paschereit

Keyword(s):

Transfer Function ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Equivalence Ratio ◽

Transfer Functions ◽

Optical Measurement ◽

Low Frequencies ◽

Fuel Flow ◽

Calibration Measurement

Equivalence ratio fluctuations are known to be one of the key factors controlling thermoacoustic stability in lean premixed gas turbine combustors. The mixing and thus the spatio-temporal evolution of these perturbations in the combustor flow is, however, difficult to account for in present low-order modeling approaches. To investigate this mechanism, experiments in an atmospheric combustion test rig are conducted. To assess the importance of equivalence ratio fluctuations in the present case, flame transfer functions for different injection positions are measured. By adding known perturbations in the fuel flow using a solenoid valve, the influence of equivalence ratio oscillations on the heat release rate is investigated. The spatially and temporally resolved equivalence ratio fluctuations in the reaction zone are measured using two optical chemiluminescence signals, captured with an intensified camera. A steady calibration measurement allows for the quantitative assessment of the equivalence ratio fluctuations in the flame. This information is used to obtain a mixing transfer function, which relates fluctuations in the fuel flow to corresponding fluctuations in the equivalence ratio of the flame. The current study focuses on the measurement of the global, spatially integrated, transfer function for equivalence ratio fluctuations and the corresponding modeling. In addition, the spatially resolved mixing transfer function is shown and discussed. The global mixing transfer function reveals that despite the good spatial mixing quality of the investigated generic burner, the ability to damp temporal fluctuations at low frequencies is rather poor. It is shown that the equivalence ratio fluctuations are the governing heat release rate oscillation response mechanism for this burner in the low-frequency regime. The global transfer function for equivalence ratio fluctuations derived from the measurements is characterized by a pronounced low-pass characteristic, which is in good agreement with the presented convection–diffusion mixing model.

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