Study on Time Histories of Heat Release Rate and Concentration of Combustion Products during a Later Half of Diesel Combustion with Multi-hole Injector

2017 ◽  
Vol 2017.55 (0) ◽  
pp. K0715
Author(s):  
Masahide NAKAMURA ◽  
Masashi NAKAMURA ◽  
Shinnosuke MIYAZAKI ◽  
Yoshiyuki KIDOGUCHI ◽  
Yuzuru NADA
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Products ◽  
Diesel Combustion ◽  
Time Histories

scholarly journals Effects of Heat Release Rate on NOx Time History in Diesel Combustion.

1996 ◽  
Vol 62 (598) ◽  
pp. 2521-2527
Author(s):  
Takuji ISHIYAMA ◽  
Kei MIWA ◽  
Satoru WATABE ◽  
Masanori HIGASHIDA
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Time History ◽  
Diesel Combustion

scholarly journals Numerical Investigation of Critical Velocity in Reduced Scale Tunnel Fire with Constant Heat Release Rate

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Ruben Mouangue ◽  
Philippe M. Onguene ◽  
Justin T. Zaida ◽  
Henri P. F. Ekobena
Keyword(s):  
Heat Release ◽  
Critical Velocity ◽  
Heat Release Rate ◽  
Release Rate ◽  
Combustion Products ◽  
Healthy Environment ◽  
Tunnel Fire ◽  
Air Supply ◽  
Minimum Velocity ◽  
Reduced Scale

When a fire occurs in a tunnel in the absence of sufficient air supply, large quantities of smoke are generated, filling the vehicles and any space available around them. Hot gases and smoke produced by fire form layers flowing towards extremities of the tunnel which may interfere with person’s evacuation and firefighter’s intervention. This paper carries out a numerical simulation of an unexpected fire occurring in a one-way tunnel in order to investigate for the critical velocity of the ventilation airflow; this one is defined as the minimum velocity able to maintain the combustion products in the downstream side of tunnel. The computation is performed successively with two types of fuels representing a large and a small heat release rate, owing to an open source CFD code called ISIS, which is specific to fires in confined and nonconfined environments. It is indicated that, after several computations of full-scale fires of 43.103 and 19.103 kJ/kg as heat release rate, the velocities satisfying the criterion of healthy environment in the upstream side of the tunnel are 1.34 m/s and 1.12 m/s, respectively.

A new concept of actively controlled rate of diesel combustion (ACCORDIC): Part II—simultaneous improvements in brake thermal efficiency and heat loss with modified nozzles

2018 ◽  
Vol 20 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Noboru Uchida ◽  
Hiroki Watanabe
Keyword(s):  
Heat Release ◽  
Heat Loss ◽  
Heat Release Rate ◽  
Release Rate ◽  
Thermal Efficiency ◽  
Air Entrainment ◽  
Diesel Combustion ◽  
Brake Thermal Efficiency ◽  
Rate Profile ◽  
Late Part

A new diffusion-based combustion concept (named it as Actively Controlled Rate of Diesel Combustion) for the confirmation of brake thermal efficiency optimum heat release rate profile based on multiple fuel injectors has been investigated. The outstanding results are; it is possible to achieve desired heat release rate profile only by the independent control of injection timing and duration of three injectors installed to a cylinder. The optimum brake thermal efficiency was not achieved with the Otto-like cycle but with the Sabathe-like cycle as predicted by a zero-dimensional thermodynamic model. Furthermore, smoke emissions were concurrently reduced with NOx emissions by increasing fuel amount from the side injectors without any deterioration in CO and total hydrocarbon emissions. On the other hand, brake thermal efficiency itself was not so improved than expected, because of lower heat release in the late part of combustion and unexpected less heat loss reduction. To solve these issues, combustion visualization and numerical simulation analysis were carried out. The results suggested that the adjacent sprays with narrower angle from each side injector deteriorated air entrainment and mixture formation, which might also result in the deterioration in wall heat loss in the expansion stroke. To solve both issues simultaneously, modified nozzle to inject against the swirl from the side injectors was utilized and achieved an improvement in both brake thermal efficiency and heat loss. That is the interdependent and reciprocal control of in-cylinder flow and fuel injection will be one of the breakthrough technologies for current trade-offs by the temporal and spatial spray flame optimization. Furthermore, the nozzle having higher flow rate with less number of orifice was utilized for the side injectors. Even though the smoke emissions were not optimized yet, brake thermal efficiency was much improved with higher heat release rate in the late part of combustion.

Scale Modeling on the Effect of Air Velocity on Heat Release Rate in Tunnel Fire

2008 ◽  
Vol 18 (2) ◽  
pp. 111-124 ◽  
Author(s):  
C. Chen ◽  
L. Qu ◽  
Y. X. Yang ◽  
G. Q. Kang ◽  
W. K. Chow
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Air Velocity ◽  
Tunnel Fire ◽  
Scale Modeling

scholarly journals Effects of Discharge Area and Atomizing Gas Type in Full Cone Twin-Fluid Atomizer on Extinguishing Performance of Heptane Pool Fire under Two Heat Release Rate Conditions in an Enclosed Chamber

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Water Mist ◽  
Pool Fire ◽  
Sauter Mean Diameter ◽  
Discharge Area ◽  
Fire Extinguishing ◽  
Enclosed Chamber

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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