Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Experimental Study

The Influence of Convection Heat Transfers for Vertical Mini-Tubes Using Solvent Carbon Dioxide and Porous Media at Supercritical Pressure

Bilal J. Kkihlefa; Ameer A. Jaddoa; Ahmed H. Reja

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1409-1419
DOI: 10.30684/etj.v39i9.2068

Porous media and solvent CO2 at supercritical pressure were investigated experimentally to study the effect of convection heat transfer in vertical mini-tubes. Mini-tubes diameter (5 and 8 mm) with medium porosity of 0.5 are proposed in experimental investigation. Experimental conditions consisted of bulk fluid, wall temperatures ranged from 33 to 55 oC, and 8 to 10 MPa of pressure. Reynolds number, Mass flow rate, and heat flux were 1750 to 21000, 0.5 to 4.5 Kg/h, and 3.25×104 to 1.1×105 W/m2 respectively. Some chemical additives like Ethanol, Chloroform, Acetone, Dimethyl sulfoxide, and Methanol were considered. A special focus was dedicated to studying the influence of heat flux, inlet temperature, and mass flow rate at measured values of wall and fluid bulk temperatures, and coefficients of local heat transfer for mini-tubes and porous media. A higher effect was noticed on the convection heat transfer by buoyancy and properties of the thermophysical variable of solvent CO2 in mini-tube at vertical position. However, when these results were compared with the controls (empty tube) shoewn dramatically different results. Heat transfer coefficient was bigger about 4 times when using the porous media tube compared with the empty type in the case of using a 5% of acetone solvent.

Shear Lag in Reinforced Concrete T-Beams with Web Openings

Eyad Kadhum Sayhood; Nisreen Saleh; Ahmed S.Hanon

Engineering and Technology Journal, 2016, Volume 34, Issue 8, Pages 1673-1687
DOI: 10.30684/etj.34.8A.17

In this paper, an extensive study is carried out 18 beams on the behavior of T-beams (8 with web openings, 10 without openings). Compressive strains distribution at the flanged are investigated with the presence of the openings in web to recheck the effective width of flange with real flange width. Parametric study are considered in this paper includes the compressive strength, longitudinal flexuralreinforcement,flangereinforcement,shear reinforcement and theweb openings (location, shape, size). Generally, standard codes of practice have overestimated effective flange width due to concentrated load effect, and codes do not take into account the web openings effect. Based on the results, the enhancement in effective width for each parameter were 9.1%-13.36%(compressive strength),10.1%-13.3%(longitudinal flexural reinforcement),7.6%-18.2%(flange reinforcement),3.35%-5.7%(shear reinforcement), the web openings reduced the effective flange width by 15% (openings at mid span ) and 5% ( openings at quarter span ) and the circular opening gavean optimum effective width better than rectangular opening were located both at quarter span.