Begell House Inc.
Heat Transfer Research
HTR
1064-2285
47
1
2016
SORET AND DUFOUR EFFECTS ON THE MHD PERISTALTIC FLOW IN A POROUS MEDIUM WITH THERMAL RADIATION AND CHEMICAL REACTION
1-28
10.1615/HeatTransRes.2015007231
Saima
Noreen
Department of Mathematics, Faculty of Science, Jiangsu University, Zhenjiang 212013, China; Department of Mathematics, COMSATS University Islamabad 45550, Park Road, Tarlai
Kalan, Islamabad 44000, Pakistan
M.
Saleem
Department of Mathematics, University of Management and Technology, Lahore 54770, Pakistan
Soret and Dufour effects
porous medium
thermal radiation
mixed convection
This study discusses the Soret and Dufour effects on the MHD peristaltic flow of a Maxwell fluid in the presence of thermal radiation and chemical reaction. The whole analysis is carried out in a porous space in a vertical asymmetric channel. A long wavelength and low Reynold number approximation is adopted. The walls are kept at different but constant temperatures and concentrations. A perturbation solution is acquired, which satisfies the momentum, energy, and concentration equations. Pressure rise per wavelength and frictional forces at the walls are computed numerically. The flow characteristics are analyzed at various pertinent parameters of interest.
NATURAL CONVECTION IN A NON-DARCY POROUS MEDIUM WITH DOUBLE STRATIFICATION AND CROSS DIFFUSION EFFECTS
29-40
10.1615/HeatTransRes.2015008037
Darbhasayanam
Srinivasacharya
Department of Mathematics, National Institute of Technology, Warangal, Telangana, 506004,
India
O.
Surender
Department of Mathematics, National Institute of Technology, Warangal-506 004, Telangana, India
natural convection
thermal stratification
solutal stratification
Soret and Dufour effects
non-Darcy porous medium
This work explores the influence of the Soret and Dufour on natural convection heat and mass transfer over a semiinfinite vertical plate with uniform and constant wall temperature and concentration in a doubly stratified fluid-saturated porous medium. The Darcy−Forchheimer model is employed to describe the flow in a porous medium. Coordinate transformation is introduced to attain the nonsimilar governing equations, and the transformed boundary-layer equations are solved numerically. The influence of the governing parameters involved in the problem on the nondimensional velocity, temperature, concentration, heat and mass transfer rates are discussed and displayed through graphs.
DETERMINATION OF CRITICAL REYNOLDS NUMBERS FOR NONISOTHERMAL FLOWS BY USING THE STOCHASTIC THEORIES OF TURBULENCE AND EQUIVALENT MEASURES
41-48
10.1615/HeatTransRes.2015014191
Artur V.
Dmitrenko
Department of Thermal Physics, National Research Nuclear University "MEPhI", 31 Kashirskoe Shosse, Moscow, 115409, Russia; Department of Power Engineering, Moscow State University of Railway Engineering (MIIT),
9 Obraztsov St., Moscow, 127994, Russia
equivalence of measures
stochastic equations
turbulence
The theory of equivalent measures and systems of stochastic equations for nonisothermal continuous medium flow is applied. The analytical expressions of critical Reynolds numbers depending on the Eckert number and initial turbulence for nonisothermal and compressible Newtonian medium flows for a smooth flat plate and a round tube are discussed. A comparison of the calculated values of the critical Reynolds numbers and experimental data is presented.
ANNULAR THERMAL-WAVE DIFFUSING MEASUREMENT METHOD FOR LOCAL THERMAL DIFFUSIVITY EVALUATION
49-69
10.1615/HeatTransRes.2015009989
Huilong
Dong
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian District, Beijing 100084, P. R. China
Boyu
Zheng
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian District, Beijing 100084, P. R. China
Feifan
Chen
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Haidian District, Beijing 100084, P. R. China
local thermal diffusivity measurement
heat conduction
principal component analysis
parameter estimation
ring areas
An annular thermal-wave diffusing measurement method for local thermal diffusivity evaluation is reported. The local thermal diffusivity is calculated by fitting all specific theoretical equation parameters estimated from the original temperature evolutions of different ring areas of the sample. The proper time and space range for thermal diffusivity calculation is determined using the principal component analysis (PCA). Compared with the conventional method, that requires the calculation area large enough to perform a complete and reliable Gaussian temperature fitting, the main advantage of this method is that the thermal diffusivity of local area in the whole mechanical structure can be evaluated just by extracting the temperature evolutions close to the heat source center. A measurement system is established with a pulsed Gaussian beam heating the sample surface and an IR camera detecting the temperature distribution. The measured radial thermal diffusivity of local area near the center of samples prepared from both Ti and Ni is in good agreement with the reference data with a 1.3% error bound at maximum.
FULL-CYCLE SIMULATION OF DIESEL ENGINE PERFORMANCE WITH THE EFFECT OF HEAT TRANSFER TO THE ENVIRONMENT
71-88
10.1615/HeatTransRes.2015008215
Deqi
Chen
Key Laboratory of Low-Grade Energy Utilization Technologies and Systems (Chongqing University),
Ministry of Education, Chongqing 40044, PR China
Xudong
Ye
Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, Chongqing University, Chongqing, 400044, China
Yiding
Cao
Department of Mechanical and Materials Engineering, Florida International University,
Miami, Florida 33174; Department of Mechanical and Materials Engineering Wright State University Dayton, OH 45435
diesel engine
mathematical simulation
heat transfer coefficient
heat losses
Heat losses to the environment may significantly affect engine performance. To accurately account for the heat-loss effect, engine performance simulation should be carried out based on a complete model which includes all four strokes of an engine cycle. In this paper, a mathematical model that includes the intake stroke, compression stroke, combustion and expansion stroke, and exhaust stroke is presented, which incorporates heat losses to the environment during the four-stroke diesel engine cycle. Through the simulation, the temperature and pressure profiles in the cylinder as well as the engine thermal efficiency are obtained. The profile of heat transfer coefficient is generated, and the effect of heat transfer to the environment on the engine performance is discussed in conjunction with the optimization of the engine performance. As a comprehensive mathematical model for engine simulation, this model is proven to be accurate, convenient, and fast, based on comparisons with available experimental data.