Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Transient


Numerical Study of Two-Dimensional Transient Natural Convection in an Inclined Shallow Porous Cavity Exposed to a Constant Heat Flux

Jasim M. A. Al-lateef; Ayad K. Hassan

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2577-2596

Numerical method is used to solve the two-dimensional transient natural convection heat transfer problem in an inclined shallow porous cavity. A constant heat flux is applied for heating and cooling all opposing walls. Solutions for laminar case are obtained within Rayleigh number varied from 20 to 500 and aspect ratio for porous cavity varied from 2 to 4. A finite difference method is used to obtain numerical solutions of full governing equations. Energy equation is solved using alternating direct implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The results are presented for the flow filed, temperature distributions, and average Nusselt number in terms of the Rayleigh number, aspect ratio, and the inclination angle of cavity. the convection becomes more and more vigorous as the orientation angle of the cavity is increased and for high Rayligh number no steady unicellular flow could be maintained inside the cavity. The effect of inclination angle on Nasselt number is more pronounced as the Rayleigh number is increased. When the inclination angle increased the Nusselt number increased and sudden transition appears and flow becomes unicellular and Nusselt number increased clearly. The value of mean Nusselt number strong function with the value of Rayleigh number, aspect ratio and the orientation of porous cavity.

A Dynamic Modeling Capability for Subcritical Vapor Compression Refrigeration System

Jafar M. Hassan; Ali H. Tarrad; Mohammed N. Abdullah

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2319-2338

In this investigation the individual component models for a typical subcritical cycle are developed based on the best published theoretical and empirical literature. The developed approach, especially for air conditioning systems, is conceptually new and can be used with modification to a variety of multicomponent system applications. The component models are then integrated and the model predictions validated against the data from various experimental test systems.
A variable speed compressor test rig was used to obtain the experimental data to be compared with the results predicted from the system model. The experimental data was monitored from the start-up of the system until the achievement of its steady-state. The system approached its steady-state after 270 sec and 360 sec for compressor speeds of 900 rpm and 1200 rpm respectively. The system disturbance was imposed by changing the operation conditions for each component. A comparison between the experimental data for these disturbances and theoretical results shows a good agreement with a discrepancy of
about (5%). The model can be used as a basis for the design, performance and efficiency of a vapor compression systems.

Effect of Dual Reinforcement on Wear Resistance by Aluminum Compacts Reinforce by SiC, Al2O3

Mohammed Moanes Ezzaldean Ali; Hanan A. R. Akkar; A. K. M. AL-Shaikhli; Ali K. Shayyish; Muhsin J. Jweeg; Wisam Auday Hussain; Mohammed T. Hussein; Mohammad A. Al-Neami; Farah S. Al-Jabary; Jafar M. Hassan; Ali H. Tarrad; Mohammed N. Abdullah; Ahmed T. Mahdi; Eyad K. Sayhood; Husain M. Husain; Nidaa F. Hassan; Rehab F. Hassan; Akbas E. Ali; Assim H Yousif; Kassim K Abbas; Aqeel M Jary; Shakir A. Salih; Ali T. Jasim; Ammar A. Ali; Hosham Salim; JafarM. Daif; Ali H. Al Aboodi; Ammar S. Dawood; Sarmad A. Abbas; Salah Mahdi Saleh; Roshen T. Ahmed; Aseel B. Al-Zubaidi; Mohammed Y. Hassan; Majid A. Oleiwi; Shaimaa Mahmood Mahdy; Husain M. Husain; Mohammed J. Hamood; Shaima; a Tariq Sakin

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 423-429

The producing composite materials of dual reinforcement in which the matrix material is aluminum reinforced with two types of ceramic particles : which are Alumina (50μm

Keywords

composite materials; wear test ; Al2O3; SiC: Al