Journal of Thermodynamics
http://www.i-scholar.in/index.php/jt
Journal of Thermodynamics is a peer-reviewed, open access journal that publishes original research articles as well as review articles in all areas of thermodynamics.en-USjther@hindawi.com (Dr. Bill Acree)jther@hindawi.com (Dr. Bill Acree)Fri, 29 Apr 2016 08:36:31 +0000OJS 2.4.2.0http://blogs.law.harvard.edu/tech/rss60Analysis of Effect of Heat Pipe Parameters in Minimising the Entropy Generation Rate
http://www.i-scholar.in/index.php/jt/article/view/97910
Heat transfer and fluid flow in the heat pipe system result in thermodynamic irreversibility generating entropy. The minimum entropy generation principle can be used for optimum design of flat heat pipe. The objective of the present work is to minimise the total entropy generation rate as the objective function with different parameters of the flat heat pipe subjected to some constraints. These constraints constitute the limitations on the heat transport capacity of the heat pipe.This physical nonlinear programming problemwith nonlinear constraints is solved using LINGO15.0 software,which enables finding optimumvalues for the independent design variables for which entropy generation is minimum.Theeffect of heat load, length, and sink temperature on design variables and corresponding entropy generation is studied. The second law analysis using minimum entropy generation principle is found to be effective in designing performance enhanced heat pipe.Rakesh Hari, Chandrasekharan Muraleedharanhttp://www.i-scholar.in/index.php/jt/article/view/97910Density and Optical Properties of {Ciprofloxacin Hydrochloride + Aqueous-Ethanol} Mixtures at 30°C
http://www.i-scholar.in/index.php/jt/article/view/97914
The paper deals with the calculation of molar refraction (<em>R<sub>M</sub></em> ) and polarizability (α) of antibiotic drug ciprofloxacin hydrochloride (<em>c</em> = 0.001-0.029 mol⋅dm<sup>−3</sup>) solutions in ethanol-water mixtures of different compositions (30, 50, and 70% v/v) from measured density (<em>ρ</em>) and refractive index (<em>n</em>) at 30°C. The effect of drug concentration and composition of ethanol-water mixtures on density and optical properties of drug solutions has been described.S. D. Deosarkar, S. S. Birajdar, R. T. Sawale, M. P. Pawar, A. M. Thakrehttp://www.i-scholar.in/index.php/jt/article/view/97914Enhancement of Integrated Solar Collector with Spherical Capsules PCM Affected by Additive Aluminum Powder
http://www.i-scholar.in/index.php/jt/article/view/97916
This research aims to study, analyze, design, and construct a solar air heater combined with an appropriate phase-change material (PCM) unit. This solar air heater is analogous to a collector integrating a thermal storage unit and a solar thermal collector. In this study, such single-pass solar air heater in amalgamation with PCMwas constructed, and several tests were conducted on this device. During the experiments for the solar collector with PCM (spherical capsules), the temperature varied between 30°C and 35°C, and the air mass flow rate ranged between 0.03 and 0.09 kg/s. Results confirmed the predicted experimental findings. With the use of paraffin wax-aluminum composite, the thermal storage efficiency of the constructed solar air heater reached a maximum value of 71% at 0.05 kg/s mass flow rate, its charging time decreased by almost 70%, and its cooling rate increased.The thermal storage efficiency of the compound composite was 76.8% at 0.07 kg/s mass flow rate. The results also indicated that the time of charging decreased by almost 60% with the use of paraffin wax-aluminum composite.Fatah O. Al Ghuol, K. Sopian, Shahrir Abdullahhttp://www.i-scholar.in/index.php/jt/article/view/97916Density and Heat Capacity of Liquids from Speed of Sound
http://www.i-scholar.in/index.php/jt/article/view/97921
Two differentmethods for deriving the density and isobaric heat capacity of liquids in the subcritical pressure range, fromthe speed of sound, are recommended. In each method, corresponding set of differential equations relating these properties is solved as the initial boundary value problem (IBVP). The initial values are specified at the lowest pressure of the range and the boundary values along the saturation line. In the first method, numerical integration is performed along the paths connecting the Chebyshev points of the second kind between the minimumandmaximumtemperature at each pressure. In the second method, numerical integration is performed along the isotherms distributed in the same way, with the temperature range being extended to the saturation line after each integration step. The methods are tested with the following substances: Ar, N<sub>2</sub>, CO<sub>2</sub>, and CH<sub>4</sub>. The results obtained for the density and isobaric heat capacity have the average absolute deviation from the reference data of 0.0005% and 0.0219%, respectively.These results served as the initial values for deriving the same properties in the transcritical pressure range up to the pressure approximately twice as large as the critical pressure.The results obtained in this pressure range have respective deviations of 0.0019% and 0.1303%.Muhamed Bijedic, Sabina Begichttp://www.i-scholar.in/index.php/jt/article/view/97921Treatment of Wastewater from a Dairy Industry Using Rice Husk as Adsorbent: Treatment Efficiency, Isotherm, Thermodynamics, and Kinetics Modelling
http://www.i-scholar.in/index.php/jt/article/view/98430
Effluent from milk processing unit contains soluble organics, suspended solids, and trace organics releasing gases, causing taste and odor, and imparting colour and turbidity produced as a result of high consumption of water from the manufacturing process, utilities and service section, chemicals, and residues of technological additives used in individual operations whichmakes it crucial matter to be treated for preserving the aesthetics of the environment. In this experimental study after determination of the initial parameters of the raw wastewater it was subjected to batch adsorption study using rice husk. The effects of contact time, initial wastewater concentration, pH, adsorbent dosage, solution temperature and the adsorption kinetics, isotherm, and thermodynamic parameters were investigated. The phenomenon of adsorption was favoured at a lower temperature and lower pH in this case. Maximum removal as high as 92.5% could be achieved using an adsorbent dosage of 5 g/L, pH of 2, and temperature of 30°C. The adsorption kinetics and the isotherm studies showed that the pseudo-second-order model and the Langmuir isotherm were the best choices to describe the adsorption behavior. The thermodynamic parameters suggested that not only was the adsorption by rice husk spontaneous and exothermic in nature but also the negative entropy change indicated enthalpy driven process.Uttarini Pathak, Papita Das, Prasanta Banerjee, Siddhartha Dattahttp://www.i-scholar.in/index.php/jt/article/view/98430Turbulent Forced Convection and Heat Transfer Characteristic in a Circular Tube with Modified-Twisted Tapes
http://www.i-scholar.in/index.php/jt/article/view/98432
Heat transfer, pressure loss, and thermal performance assessment in a circular tube heat exchanger with modified-twisted tapes are reported. The rectangular holes are punched out from the general twisted tape to reduce the pressure loss. The influences of the hole sizes (<em>l/D</em>, LR = 0.30, 0.44, 0.78, and 0.88) and twisted ratios (<em>y/D</em>, TR = 1, 1.5, 2, and 4) for the single and double twisted tapes are investigated with a numerical method at turbulent regime, Re = 3000.10,000.The finite volume method and the SIMPLE algorithm are used to investigate for the current research. The numerical results are reported in terms of flow structure and heat transfer behavior and compared with the smooth tube and the regular twisted tape. It is found that the modified-twisted tape provides higher heat transfer rate than the smooth tube due to the longitudinal vortex flows, created by the twisted tape.The longitudinal vortex flows help to increase fluid mixing. The rectangular punched holes of the twisted tape can reduce the pressure loss of the heating system. In addition, the maximum thermal enhancement factor is around 1.39 and 1.31 for the double twisted tape and single twisted tape, respectively, at Re = 3000, LR = 0.78, and TR = 1.Amnart Boonloi, Withada Jedsadaratanachaihttp://www.i-scholar.in/index.php/jt/article/view/98432Kelvin's Dissymmetric Models and Consistency Conditions of Multicomponent Gas-Liquid Equilibrium and Capillary Condensation
http://www.i-scholar.in/index.php/jt/article/view/98433
To describe phase equilibrium of mixtures,we develop a non classical approach based on using different equations of state for gas and liquid. We show that not all the types of EOS are admissible but only those which verify some specific conditions of consistency. We developed the mathematical theory of this new approach for pure cores and for mixtures, in presence and absence of capillary forces, which leads to explicit analytical relationships for phase concentrations of chemical components. Several examples of comparison with experimental data for binary and ternary mixtures illustrate the feasibility of the suggested approach.Mikhail Panfilov, Alexandre Koldobahttp://www.i-scholar.in/index.php/jt/article/view/98433Elastodynamic Response of Thermal Laser Pulse in Micropolar Thermoelastic Mass Diffusion Medium
http://www.i-scholar.in/index.php/jt/article/view/98435
The present investigation deals with the deformation in micropolar thermoelastic diffusion medium due to inclined load subjected to thermal laser pulse. Normal mode analysis technique is used to solve the problem. The inclined load is assumed to be a linear combination of a normal load and a tangential load. The closed form expressions of normal stress, tangential stress, couple stress, temperature distribution, and mass concentration are obtained. A computer program has been developed to derive the physical quantities numerically. The variation of normal stress, tangential stress, coupled stress, temperature change, and mass concentration is depicted graphically to show the effect of relaxation times and mass concentration. Some particular cases of interest are deduced from the present investigation.Rajneesh Kumar, Arvind Kumarhttp://www.i-scholar.in/index.php/jt/article/view/98435Effect of Magnetic Field on Mixed Convection Heat Transfer in a Lid-Driven Square Cavity
http://www.i-scholar.in/index.php/jt/article/view/98440
The effect of magnetic field on fluid flow and heat transfer in two-dimensional square cavity is analyzed numerically.The vertical walls are insulated; the top wall is maintained at cold temperature, Τ<sub>c</sub> while the bottom wall is maintained at hot temperature, Τ<sub>η</sub> where Τ<sub>η</sub> > Τ<sub>c</sub> The dimensionless governing equations are solved using finite volume method and SIMPLE algorithm. The streamlines and isotherm plots and the variation of Nusselt numbers on hot and cold walls are presented.N. A. Bakar, A. Karimipour, R. Roslanhttp://www.i-scholar.in/index.php/jt/article/view/98440