Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Enthalpy Method

Analysis of Thermal and Insulation Performance of Double Glazed Window Doped With Paraffin Wax

Jalal M. Jalil; Salih M. Salih

Engineering and Technology Journal, 2020, Volume 38, Issue 3A, Pages 383-393
DOI: 10.30684/etj.v38i3A.448

In this paper, a numerical investigation has been performed to study the effect of varying the thermal properties of the paraffin wax on the performance of a double glazed window doped with it during the summer climate of Baghdad (33.3 °N, 44.4 °E). Using FORTRAN (f 90) constructed computer program, finite difference combined with the enthalpy method was utilized to deal with the conduction with phase change problems within the wax. Results obtained show that increasing the density, latent heat, and thickness of the paraffin wax PCM) would increase the temperature-time lag and reduce the temperature decrement factor of the double glazed window, and as a result, improve comparatively the performance of the unit. In contrast, changing the specific heat capacity of the paraffin wax is not a productive (inefficient) technique to develop the performance of the unit. Besides, the recommended thickness of the window (thickness of the PCM) under the ambient condition of Baghdad should be 20 mm or higher.

Numerical and Experimental Prediction of Food Freezing

Soundus S. AL-Azaw; Jalal M. Jalil

Engineering and Technology Journal, 2012, Volume 30, Issue 13, Pages 2315-2340

In this study the freezing of foods was studied numerically and experimentally.
Different kinds of foods have been studied numerically (Meat, Broccoli, Perch and
Banana), while the experimental work is applied to meat only. In numerical solution
enthalpy transformation method is used to transfer the energy equation into a nonlinear
equation with a single dependent variable E (enthalpy). The discretization of
energy equation in three dimensions was solved with phase change problem
employing the control-volume finite-difference. The numerical results of the enthalpy
method were compared with experimental results and were satisfactory. The freezing
process of foods differs from one to other due to thermal property differences, water
content and freezing point. Low water content leads to smooth cooling rate and short
constant temperature region while high water content leads to long constant
temperature region.