Begell House Inc.
Heat Transfer Research
HTR
1064-2285
50
11
2019
EXPERIMENTAL INVESTIGATIONS OF FLAME PATTERNS OBSERVED FOR LPG/AIR PREMIXTURE USED IN SMALL-SCALE SWISS ROLL COMBUSTOR
1023-1041
Sagar B. Mane
Deshmukh
Department of Mechanical Engineering, Sathyabama Institute of Science and Technology, Chennai
600119, Tamilnadu, India
A.
Krishnamoorthy
Department of Mechanical Engineering, Sathyabama Institute of Science and Technology, Chennai
600119, Tamilnadu, India
V. K.
Bhojwani
Department of Mechanical Engineering, Jayawantrao Sawant College of Eng., Pune 411028,
Maharashtra, India
The present paper discusses testing of a small-scale Swiss roll combustor with two rectangular adjacent channels. Swiss roll combustors were tested using a liquefied petroleum gas (LPG) and an air pre-mixture. The following parameters, viz., the mixture equivalence ratio, mixture flow rate, and Swiss roll combustor channel depth were varied and their effect on the occurrence of different flame patterns formed in the combustor is monitored and reported. The flow rate of LPG was varied in the range from 0.25 LPM to 0.55 LPM. Nine different types of flame patterns were observed in the combustor, viz. planar, concave (or U-shaped), conical with short height and large base, conical with larger height and small base, elliptical, triangular, circular, triangular with tail, and elliptical with tail. Triangular flame with tail achieved highest combustion space temperatures as compared to other flame types listed above. The triangular flame with tail was generally observed for maximum number of Swiss roll combustor models tested (SW10, SW15, and SW20) at a wide variety of flow rates in comparison with other eight flame types. The lowest combustion space temperature was observed for planar flame type for which flame stability was also achieved for a narrow range of flow rates. Swiss roll combustors with higher channel depths showed higher maximum temperatures compared to the lower depth combustors. A flame with different pattern/shapes is observed in different regions in the combustion space of the combustor. A planar flame was noticed below 5-mm depth combustor. The tests indicated that the flame characteristics/patterns are strongly dependent on the mixture equivalence ratio, mixture flow rates, combustor depth, and heat recirculation from products to reactants.
FREE CONVECTION AND ENTROPY GENERATION IN A CuO/WATER NANOFLUID-FILLED TRIANGULAR CHANNEL WITH SINUSOIDAL WALLS
1043-1059
Alireza
Rahimi
Faculty of Energy, University of Kashan, Kashan, Iran
Navid
Vafa
School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
Morteza
Bayati
Department of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
Abbas
Kasaeipoor
Faculty of Engineering, Department of Mechanical Engineering, University of Isfahan, Hezar Jerib
Avenue, Isfahan 81746-73441, Iran
Hamidreza
Khakrah
Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran
Emad Hasani
Malekshah
School of Mathematical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
The fluid flow, heat transfer, and entropy generation due to natural convection phenomenon in a fluid channel are investigated. The configuration of the channel is triangular. Moreover, the bottom and right walls are sinusoidal. The channel contains some circular bodies of constant high and low temperatures which serve as simplified fluid injection pipes. The channel is filled with CuO-water nanofluid; the Brownian motion and its influences on the dynamic viscosity are considered using the Koo-Kleinstreuer-Li (KKL) model. The effect of the shape of nanoparticles on the thermal conductivity is studied using shape factor. The finite volume method is employed to simulate natural convection. The Rayleigh number (103 < Ra < 106), solid volume fraction of nanofluid (φ = 0, 0.01, 0.02, 0.03, and 0.04), and thermal arrangements of internal pipes (Case A, Case B, Case C, and Case D) are considered as governing parameters. Impact of these governing parameters on the streamlines, heat transfer rate, local and total entropy generation and heatlines are studied, comprehensively. Overall, the results show that the heat transfer rate has direct relationship with the Rayleigh number and nanoparticle concentration. On the other hand, the entropy generation has direct and reverse relationship with the Rayleigh number and nanoparticle concentration.
EFFECTS OF CHEMICAL REACTION ON THIRD-GRADE MHD FLUID FLOW UNDER THE INFLUENCE OF HEAT AND MASS TRANSFER WITH VARIABLE REACTIVE INDEX
1061-1080
Ambreen Afsar
Khan
Department of Mathematics & Statistics, FBAS, IIU, Islamabad, 44000, Pakistan
Syeda Rida
Bukhari
Department of Mathematics & Statistics, FBAS, IIUI, Islamabad, Pakistan
Marin
Marin
Department of Mathematics and Computer Science, Transilvania University of Brasov, 500093
Brasov, Romania
Rahmat
Ellahi
Center for Modeling & Computer Simulation, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran-31261, Saudi Arabia; Department of Mathematics and Statistics, FBAS, IIUI, Islamabad, Pakistan
In this work, third-grade magnetohydrodynamic fluid with variable thermal conductivity and chemical reaction over an exponentially stretching surface is examined. Effects of heat and mass transfer with heat source and sink are also analyzed. The analytical solutions are obtained by means of the homotopy analysis method (HAM). Convergence analysis of established solutions is also proposed. The physical interpretation of emerging parameters for velocity, temperature, and concentration profiles are presented by graphical and tabular illustrations. It is found that a rise in the magnetic parameter leads to a reduction in the thickness of boundary layer, whereas the reverse scenario is noticed for the case of heat sink and source.
THERMAL BEHAVIOR OF THE POT-IN-POT REFRIGERATOR: SIMULATION AND EXPERIMENTAL APPROACH
1081-1103
Sidharth S.
Chakrabarti
OP Jindal University, Raigarh, Chattisgarh, 496001, India
P. K.
Das
Indian Institute of Technology, Kharagpur, West Bengal, 721302, India
Evaporative cooling is basically a passive cooling technique in which a body is cooled by the evaporation of water from its surface. The paper deals with the two-dimensional unsteady mathematical model for a clay pot refrigerator and validated with the experimental results obtained in the environment chamber. The tests were conducted at different relative humidities and dry bulb temperatures and the test results were utilized to obtain the pot efficiency, COP, and the variation of other parameters with the ambient conditions. The presence of the porous medium as clay and sand was given a special attention in modeling the clay pot. The results were also validated with numerical code developed for the above case. The effects of ambient conditions on mass transfer coefficient, evaporation loss, hydraulic conductivity of clay and sand were studied and analyzed.
BUOYANCY-DRIVEN CHEMICALIZED EMHD NANOFLUID FLOW THROUGH A STRETCHING PLATE WITH DARCY–BRINKMAN–FORCHHEIMER POROUS MEDIUM
1105-1126
Satyaranjan R.
Mishra
Department of Mathematics, Siksha 'O' Anusandhan University, Bhubaneswar-751030, Odisha,
India
Anwar
Shahid
School of Mathematics and Information Sciences, Guangzhou University, Guangzhou 510006,
China
Swarnalata
Jena
Department of Mathematics, Centurion University of Technology and Management, Bhubaneswar,
India
Muhammad Mubashir
Bhatti
Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Yanchang
Road, Shanghai 200072, China;
Department of Mathematics, Shanghai University, Shanghai 200444, China
The present paper analyzes steady chemicalized free-convection flow of an electrically conducting nanofluid fluid past a stretching plate installed inside a permeable media accountable to extrinsic magnetic field with nonuniform heat source/ sink. The solution of a two-dimensional problem comprises similarity transformation. The governing modeled nonlinear partial differential equations (PDEs), i.e., momentum equation and heat/mass transfer equations are brought down into nonlinear ODEs. The resulting equations are solved by a numerical method labeled as the spectral local linearization method (SLLM). The numerical outcomes for skin friction, Nusselt number, and Sherwood number are presented in a table. The survey made by preceding investigators is equated with the current study as a peculiar case in the absence of solutal buoyancy, Darcy dissipation, and chemical reaction. The extensive discoveries are: the influence of electromagnetic force reduces the skin friction contribution to flow stability. Liquid medium diffusion greatly compensates the loss due to the Darcy dissipation enhancing the rate of mass transfer.