https://ds.univ-oran2.dz:8443/jspui/handle/123456789/1833 2026-07-27T11:01:29Z 2026-07-27T11:01:29Z Belarbi, Boumediene Benabdallah, Tawfik Abdi, Ghezail https://ds.univ-oran2.dz:8443/jspui/handle/123456789/1889 2019-11-28T10:45:01Z 2016-03-01T00:00:00Z

Titre: Implementation of a New Dimensional Qualification (DQ) Method for an Open Access Fused Deposition Modeling 3D Printer Auteur(s): Belarbi, Boumediene; Benabdallah, Tawfik; Abdi, Ghezail Résumé: The present work implements for the first time a dimensional qualification procedure of rapid prototyping process in the case of 3D Open Access printer. Thus, to improve this, the author proposes a developed methodology and specific procedure with an implemented test pieces measurement. The experimental results are compared in accordance with the designer specifications which resulted in a methodological qualification procedure developed in the research laboratory. In addition, this procedure provides an accurate information about the manufacturing process quality for a 3D printing's Fused Deposition Modelling (FDM); taking into account the upstream and downstream of the deposition material. This paper presents a comparative evaluation between the design data and measurements realized on a production model. The obtained result serves to confirm the quality of the machine according to the manufacturer's specifications and allows its qualification. Once the dimensional qualification (first stage) is achieved, it could be considered as a prelude to a geometric qualification (second stage). Then, a complete validation is done on a machine randomly taken from a series of commercial printers. This methodology has shown its efficiency with current ‘Open Access’ 3D printers and could be used as quality labelling tool.

2016-03-01T00:00:00Z Benabdallah, Tawfik Ghezail, Abdi Ait Hamadouche, Mohamed https://ds.univ-oran2.dz:8443/jspui/handle/123456789/1888 2019-11-28T10:30:51Z 2015-05-01T00:00:00Z

Titre: New Enhanced Cooling Towers Models by Implementation of Drift Losses Calculations Auteur(s): Benabdallah, Tawfik; Ghezail, Abdi; Ait Hamadouche, Mohamed Résumé: Currently, the most commonly used model to simulate cooling tower operation is Merkel’s model, though its implementation involves various hypotheses proving sometimes to be not suitable for real applications. Research demonstrates that it is possible to substitute this model by a more simplified one introduced by Arns and Klenke. Although this substitution has given satisfactory results for both models, it is found that the water loss (also called the drift losses) is neglected. This work tends to improve Merkel and Simplified models by implementing the calculation of water losses by drift as well as contributing to enrich the simplified model so as to substitute Merkel’s model. This paper describes the new formulations of the standard and simplified models introducing the drift losses calculation. This latter represents water mass flow rate escaping from the cooling system in the form of droplets and mechanically driven in the outlet air flow. The authors have conducted a comparative study of the results obtained with these improved models. This study shows very good agreement between the two models which allows the substitution of Merkel’s model by Simplified model and they offer a better simulation for the operation of counter flow cooling towers.

2015-05-01T00:00:00Z Ghezail, Abdi Benabdallah, Tawfik https://ds.univ-oran2.dz:8443/jspui/handle/123456789/1887 2019-11-28T10:16:36Z 2015-01-01T00:00:00Z

Titre: New Extended Simulation Method at Out-Design Operating Conditions for Cooling Towers Auteur(s): Ghezail, Abdi; Benabdallah, Tawfik Résumé: The present article describes an improved formulation of Arns and Klenke’s Simplified Model, based on Merkel’s Standard Model. The point of this is to enable better simulation of the performances for open counterflow cooling towers under operating conditions different from those set in the manufacturers’ manuals. It aims to demonstrate that it is possible to improve Arns and Klenke’s used models to simulate the cooling towers and enable these models to evaluate their performances in greater detail. To complement the comparative study of these two models, the Simplified Model has been extended to two new cases. Our contribution consists in proposing an innovative method that makes it possible on the one hand to compensate for the shortage of validation data since manuals do not mention all the necessary performances for simulation, and on the other hand to offer a new way of validating the obtained results. The suggested method is based on the use of the stationary operating states of the tower as a means to validate simulation. Numerical results have been successfully compared with those obtained by the Standard Method. The results are satisfactory, show the limitations of each model and open ways to further improvements.

2015-01-01T00:00:00Z