Anand Shukla^a, Alok Chaube^b, Shailesh Guptac^†, Arvind Sirsath^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.14

Abstract One of the traditional methods used to improve the efficiency of a gas turbine is to increases the inlet temperature; thereby increasing the power output and in turn, the efficiency. The internal cooling passages of blades are roughened by artificial roughness to improve the cooling performance. The present study investigates the convective heat transfer and friction factor (pressure drop) characteristics of a rib-roughened square duct. The test section of the duct is roughened on its top and bottom wall with V and ᴧ- shaped square ribs. In the study, the Reynolds number (Re) varied from 10,000… More >

Benjamin Lepers^a,*, Aditya Putranto^b,c, Martin Umminger^d, Guido Link^a, John Jelonnek^a

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-11, 2014, DOI:10.5098/hmt.5.13

Abstract The use of high power microwaves to perform explosive spalling of surface concrete is a promising technique with applications in the area of concrete facilities decommissioning. The mechanism that creates explosive spalling is an interactive process of the thermal stress from high temperature gradients and the pore pressure generated from the water vaporization. In order to better predict the total stress distribution, the temperature has to be calculated by including the effect of water vaporization and water transport through a porous medium. In this paper, a one dimensional model solving the heat and diffusion equation More >

Amnart Boonloi^*

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-12, 2014, DOI:10.5098/hmt.5.8

Abstract A mathematical analysis of the heat transfer enhancement, thermal performance and flow configurations in a heat exchanger square duct with diagonal inserted plate vortex generators is presented. The 30o V–shaped baffles are modified and placed on the double sides of the thin plate or frame (with no plate) which inserted diagonally in the square duct. The effects of blockage ratio (b/H, BR), the pitch ratio (p/H, PR), flow direction (V–Downstream and V–Upstream) and configuration of inserting plate are investigated for Reynolds number based on the hydraulic diameter of the square duct, D_h, Re = 100 –… More >

Sally M. Smith^*, Brenton S. Taft^† , Jacob Moulton

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-9, 2014, DOI:10.5098/hmt.5.6

Abstract This study investigates the wettability of fluid-solid interactions of interest for oscillating heat pipe (OHP) applications. Measurements were taken using two techniques: the sessile drop method and capillary rise at a vertical plate. Tested surface materials include copper, aluminum, and Teflon PFA. The working fluids tested were water, acetone, R-134a, and HFO-1234yf. A novel low-pressure experimental setup was developed for refrigerant testing. Results show that the refrigerants have significantly lower hysteresis than the water and acetone-based systems, which is thought to lead to better heat transfer in OHP design. More >

Zhen Tian^a,*, Wenbo Jin^a, Lei Wang^b, Zhi Jin^c

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-8, 2014, DOI:10.5098/hmt.5.5

Abstract Taking the axial heat conduction of wax deposition layer into account, a two-dimensional heat transfer model of calculating the temperature profile inside wax deposition layer was deduced and established based on the energy balance equation, the finite difference method was used to solve this model, and the influence of axial heat conduction on the distribution law of temperature profile inside the wax deposition layer under different boundary conditions and thickness were discussed. The results showed that: Temperature profile inside wax deposition layer in middle region of testing pipe section was mainly influenced by axial heat More >

Machireddy Gnaneswara Reddy^*

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-9, 2014, DOI:10.5098/hmt.5.4

Abstract The numerical solution of transient natural convection MHD flow past a vertical cylinder embedded in a porous medium with surface temperature and concentration along with thermal radiation is presented. The temperature and concentration level at the cylinder surface are assumed to vary as power law type functions, with exponents m and n respectively in the stream wise co-ordinate. The governing boundary layer equations are converted into a non-dimensional form. A Crank-Nicolson type of implicit finite-difference method is used to solve the governing non-linear set of equations. Numerical results are obtained and presented with various thermal More >

Bouzo CA, JC Favaro

Phyton-International Journal of Experimental Botany, Vol.83, pp. 167-170, 2014, DOI:10.32604/phyton.2014.83.167

Abstract The aim of this work was to compare methods to predict the time of anthesis in tomato (Solanum lycopersicum L.). Two independent experiments were carried out using seeds of the Tauro commercial hybrid. Daily maximum and minimum air temperatures were measured by means of an electronic thermometer with data storage; the photoperiod was calculated using a mathematical procedure. The moment at which each inflorescence presented 50% of its flowers in anthesis was recorded. The use of calendar days (CD) had a high dispersion, which was measured with a variation coefficient (VC) higher than 3.70% for all More >

Rodríguez-González RE¹, JJ Paz Hernández¹, CG Iñiguez Monroy³, EO Rueda Puente², L Avendaño-Reyes¹, M Cruz-Villegas¹, CE Ail-Catzim¹, M Stoycheva⁴, R Koytchev Zlatev⁴, P Renganathan², AM García López¹

Phyton-International Journal of Experimental Botany, Vol.83, pp. 65-70, 2014, DOI:10.32604/phyton.2014.83.065

Abstract The aim of this study was to evaluate grain yield (RG) stability of some commercial wheat varieties, and to assess the stability of other parameters which are not typically measured for grain release purposes: performance of straw (RP), weight per hectoliter (PH), white belly (PB), harvest index (IC), grain protein (PG) and gluten strength (W). The evaluation was performed with the wheat varieties Cachanilla F-2000 (C), Yécora F-70 (Y) and Triguenio F-00 (TR), in El Valle de Mexicali, Baja California under four test environments, with the application of the Eberhart and Russell model. The study More >

Chein-Shan Liu ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.5, pp. 371-391, 2014, DOI:10.3970/cmes.2014.099.371

Abstract We recover an unknown initial temperature for a nonlinear heat conduction equation u_t(x,t) = u_xx(x,t) + H(x,t,u,u_x), under the Cauchy boundary conditions specified on the left-boundary. The method in the present paper transforms the Cauchy problem into an inverse heat source problem to find F(x) in T_t(x,t) = T_xx(x,t) + H + F(x). By using the GL(N,R) Lie-group differential algebraic equations (LGDAE) algorithm to integrate the numerical method of lines discretized equations from sideways heat equation, we can fast recover the initial temperature and two boundary conditions on the right-boundary. The accuracy and efficiency are confirmed by comparing the More >

Weichung Yeih^1,2, I-Yao Chan¹, Chia-Ming Fan¹, Jiang-Jhy Chang¹, Chein-Shan Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.99, No.2, pp. 169-194, 2014, DOI:10.3970/cmes.2014.099.169

Abstract In this paper, the Cauchy inverse problem of the nonlinear steady-state heat equation is studied. The double iteration process is used to tackle this problem in which the outer loop is developed based on the residual norm based algorithm (RNBA) while the inner loop determines the evolution direction and the modified Tikhonov's regularization method (MTRM) developed by Liu (Liu, 2012) is adopted. For the conventional iteration processes, a fixed evolution direction such as F, B⁻¹F, B^TF or αF+(1-α)B^TF is used where F is the residual vector, B is the Jacobian matrix, the superscript '-1' denotes the inverse, the… More >