Begell House Inc.
Heat Transfer Research
HTR
1064-2285
47
11
2016
A NEW SEMIEMPIRICAL MODEL FOR THE MAXIMUM TEMPERATURE UNDER THE CEILING IN URBAN TRAFFIC LINK TUNNEL FIRES
989-1011
10.1615/HeatTransRes.2016010488
Sicheng
Li
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, 100124, China; Department of Fire Command, The Chinese People's Armed Police Force Academy, Lang fang, Hebei, 065000, China
W.
Wang
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, 100124, China
Y. H.
Zhao
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, 100124, China
X. G.
Dong
College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, 100124, China
Urban Traffic Link Tunnel fire
maximum temperature
numerical simulation
FDS
The Urban Traffic Link Tunnel (UTLT) is an innovative underground transportation system for the modern metropolis, typically consisting of a main tunnel and several linked tunnels. To provide proper fire protection to the UTLT structure, the maximum temperature beneath the ceiling needs to be determined. However, as the effective height of the UTLT is lower than that of a normal tunnel, the maximum temperatures under the UTLT ceiling are different from those in normal tunnels. A theoretical analysis and CFD simulation were performed in this work to estimate the maximum temperature under the ceiling in UTLT. The smoke temperatures at 0.2 m under the ceiling of the UTLT were computed for different heat release rates, longitudinal ventilation velocities, and tunnel heights. Based on the simulation results, a new semiempirical model for the maximum temperature under the ceiling during UTLT fires has been developed. The comparison of the new model predictions with experimental data indicates that the model can predict experimental results fairly well and is suitable for the UTLT fire protection design.
DETERMINING A POINT HEAT SOURCE POSITION IN A 2D DOMAIN USING THE BI-OBJECTIVE ANT COLONY OPTIMIZATION
1013-1033
10.1615/HeatTransRes.2016007400
Bohan
Li
School of Energy and Power Engineering, University of Shanghai for Science and Technology, 516 Jun Gong Road, Shanghai, 200093, P. R. China
Mei
Lu
School of Energy and Power Engineering, University of Shanghai for Science and Technology, 516 Jun Gong Road, Shanghai, 200093, P. R. China
inverse heat conduction problems
inverse heat source problems
ant colony optimization (ACO)
swarm intelligence
bi-objective functions
An optimization algorithm called ant colony optimization combined with numerical methods is applied to determine the unknown position of a point heat source in a two-dimensional steady-state heat conduction problem with the Dirichlet and Robin boundary conditions. The determination is based on the temperature measurements at some points on the boundaries of the solving domain. Instead of the actual experiments, the temperature measurements at the measurement points are obtained from numerical simulations with the exact position of the point heat source. The inverse problem is solved as an optimization problem in which bi-objective functions are maximized by the ant colony optimization algorithm. The bi-objective functions include both the root-mean-square deviation and the correlation coefficients between the computed and measured temperatures at the measurement points. Each of the bi-objective functions is associated with one of the coordinates of the heat source position. They reflect the features of heat conduction problems and therefore can increase the rate of convergence of the inverse problem. Several numerical experiments are performed to test the proposed mathematical model under different circumstances. The results show that it can find the position of the point heat source accurately and efficiently with the average calculation times of the direct problems being less than 0.8% of all the possible positions.
INTEGRAL METHOD OF BOUNDARY CHARACTERISTICS: THE DIRICHLET CONDITION. PRINCIPLES
1035-1055
10.1615/HeatTransRes.2016014882
Valery A.
Kot
A. V Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, Minsk, Belarus
heat conduction equation
heat balance integral method
temperature disturbance front
boundary characteristics
integral identity
weight function
An integral method related to approximate analytical methods of solution of the boundary-value evolution-type problems by introducing the disturbance front is suggested. The method is based on two sets that include boundary characteristics, i.e., n-multiple integrals and k-multiple time derivatives for the functions from the Dirichlet condition. The existence of two sequences of identical equalities involving either integral or differential boundary characteristics has been proved for the parabolic partial differential equation. The general scheme of the method is presented by an example of the generalized equation of unsteady-state heat conduction in an infinite region bounded from inside by plane, cylindrical or spherical surfaces. Four versions of calculation of the disturbance front are suggested; three of these versions move the solution to the space of algebraic equations.
SYNGAS PRODUCTION FROM PROPANE−BUTANE MIXTURES USING A HIGH-VOLTAGE ATMOSPHERIC PRESSURE DISCHARGE PLASMA
1057-1072
10.1615/HeatTransRes.2016016411
Feraih Sheradh
Alenazey
King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh 11442, K.S.A.; Prince Sattam bin Abdulaziz University (PSAU), Riyadh, K.S.A
Ahmed A.
Al-Harbi
King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh 11442, K.S.A.
A. P.
Chernukho
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
Yuri M.
Dmitrenko
Private R&D Enterprise "Advanced Research & Technologies (ART)", Minsk, Republic of Belarus
Alexei N.
Migoun
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
Serguei A.
Zhdanok
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
plasma
syngas production
This paper presents a part of international project results, which aims at impoving the environmental performance of the classic internal combustion engine with spark ignition by admixing on-board generated syngas into the engine's working mixture. Different kinds of fuel are considered, but here we present the results on LPG only. The conversion of propane−butane (LPG) mixture with air into syngas via a high-voltage atmospheric pressure discharge process has been investigated experimentally and theoretically. The process characteristics were measured at two gas flow rates through the discharge, namely 10 and 14.75 L/min and the equivalence ratio of the initial mixture was varied in the range 1.7−3.0, while the discharge energy input was between 600 and 1300 W. A conversion degree of about 77% was achieved for H2, which corresponds to a 23% H2 concentration in the conversion products. A numerical model of the process, which assumes that the role of the discharge in the conversion is purely thermal in nature, has been developed. The developed model has outstanding agreement with the experimental results obtained from a plasma discharge system.
REDUCING POLLUTION EMISSIONS BY ADDING SYNGAS GENERATED BY A PLASMA-ASSISTED GASOLINE CONVERTER IN THE INTAKE MANIFOLD OF A GASOLINE ENGINE WITH ELECTRONIC FUEL INJECTION SYSTEM
1073-1082
10.1615/HeatTransRes.2016016579
Ahmed A.
Al-Harbi
King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh 11442, K.S.A.
Feraih Sheradh
Alenazey
King Abdulaziz City for Science and Technology (KACST), P.O. Box 6086, Riyadh 11442, K.S.A.; Prince Sattam bin Abdulaziz University (PSAU), Riyadh, K.S.A
Alexei N.
Migoun
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
Yuri M.
Dmitrenko
Private R&D Enterprise "Advanced Research & Technologies (ART)", Minsk, Republic of Belarus
Serguei A.
Zhdanok
Advanced Research and Technologies LLC, Research and Development Enterprise, 2a Tolbukhin Str., room 7, Minsk, 220012, Belarus
pollution
emission
combustion
engine
syngas
plasma
The objectives of this study were to determine the performance and exhaust emissions of a gasoline engine with a fuel injection system (Subaru EH72 FI) modified for operation with addition of some amount of synthethis gas ("syngas") containing hydrogen in the intake manifold and to compare the results with those obtained for gasoline operation at the same engine load and crankshaft speed. As the engine working load, Endress ESE 1506 DSG-GT ES DUPLEX electric generator with effective output in the range from 3 to 15 kW is used. Syngas was generated by partial oxidation of gasoline with air in a plasma-assisted fuel converter. Steam was added to the gasoline−air converter fuel mixture to reduce the amount of soot produced in a plasma reactor, and thereby increase its reliability and operational life. A completely automated engine and plasma converter test bench was developed. Experimental results clearly demonstrate substantial reduction in the NOx engine emissions when hydrogen-rich synthesis gas generated by a plasma-assisted fuel converter was added to the intake manifold of the tested engine. The most prominent reduction in harmfull pollutions is observed for lean conditions. Meanwhile total gasoline consumption (including gasoline needed for the plasma-assisted converter) with syngas addition increases compared to the original engine. This increase ranges from 1.05 for a stochiometric composition of the fuel mixture to 1.15 times for a lean mixture (excess air coefficient of the fuel mixture λ = 1.26). As a continuation of this work, investigations of ultralean regimes (λ ~ 1.43−1.67) are scheduled to validate the theoretical results obtained in (Migun et al., 2006).