Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Numerical simulation

Modeling of Air-Water Filled Rubber Dam Under Hydrostatic Conditions

Qusay S. Khaleel; Thair S. Khayyun; Khudhayer N. Abdullah

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1976-1987
DOI: 10.30684/etj.v39i12.1968

Inflatable dams, also called rubber dams, are flexible cylindrical inflatable and deflatable structures attached to a rigid base; these dams are basically cylindrical tubes made of rubberized material and inflated by air, water, or a combination of the two. In this paper, the air/water inflatable dam was studied and analyzed numerically using ANSYS software. The 3-parameter Mooney-Rivlin Model was used to model the rubber material of the dam. At first, a physical model from literature was used to calibrate the results of the ANSYS software, and then a new model was analyzed with different dimensions and conditions. Thirty-six simulations were made using the ANSYS software to calibrate the software, based on experimental results from the literature. The simulations achieved a very low error rate compared to the experimental findings, with a maximum error rate of 1.45 percent. After that, a new air/water-filled dam model simulation was carried out. The new inflatable dam was analyzed with large dimensions that can be used to reserve water at high elevations. Several water heights (2, 4, 6, 8, and 10 m) were used as input at the upstream of the dam, and their effect on the dam body was verified on the assumption that there was no water downstream of the dam for all simulations. The height of the used inflatable dam was assumed to be 11 meters (first 5.5 m water pressure and the second 5.5m different air pressure values), and the bottom gaskets was 9.7 meters wide. It is evident from the analysis that the upstream water appears to push the dam to the right side (towards downstream), causing a change in dam equilibrium shape. The difference in the cross-sectional equilibrium profile of the dam is due to the change in air and water pressures on the element. Thus, it changes the tension and slope of the dam membrane elements. The simulation results showed that the membrane tension increases as the upstream head increases, and as the internal pressure increases, the tension increases. This rise in tension as the upstream head rises may be due to the rise in the forces on the element, and hence the membrane tension increases.

Investigation of Thickness Distribution Variation in Deep Drawing of Conical Steel Products

Muhsin J. Jweeg; Adnan I. mohammed; Mohammed S. Jabbar

Engineering and Technology Journal, 2021, Volume 39, Issue 4A, Pages 586-598
DOI: 10.30684/etj.v39i4A.1908

This study investigates the thickness variation behavior of deep drawing conical products under the effect of different forming parameters such as die wall inclination angle, punch velocity, sheet thickness, and sheet metal type. Two types of sheet metal were used, low carbon (AISI 1008) and galvanized steel sheets, of 110 mm diameters circular blanks at 0.9 and 1.2mm thickness formed by tooling set (punch, die, and blank holder). The conical dies inclination angles were at 70ᵒ, 72ᵒ, and 74ᵒ where, the punch velocity was 100, 150, and 200 mm/min. Numerical simulation was conducted using ABAQUS 6.14 where a dynamic explicit solver was used to perform forming of conical products. The results show that maximum thinning occurs at punch nose radius region and maximum thickening in sidewall region and thinning are increased with the increasing of die sidewall angle and sheet thickness. In regard to sheet type, the Lankford coefficients r-value shows a great role in thinning behavior with respect to rolling (r-values direction). The results have shown a good agreement between experimental and numerical work with a maximum discrepancy of 5%.

Temperature Control of a Target Plate under Variable Flow of Impinging Air from an Orifice

Adnan A. Abdel Rasool; Yahya A. Faraj; Roaad K. Mohammed A

Engineering and Technology Journal, 2014, Volume 32, Issue 12, Pages 3009-3026

This work concerns with experimental and numerical study for the cooling characteristics of a target plate under the effect of air impingement from orifice of different sizes D of (5,10,15 and 20 mm). A centrifugal blower was used for air impinging with jet velocity in the range (18-40 m/s). Tested Reynolds number Re is in the range of (7100-44400) with orifice to plate spacing ratio H/D of (2,4,6,8). Numerical analysis using CFD commercial code Fluent version 14.5 with K-ε RNG turbulence model has been used to simulate the flow and heat transfer in impingement jet. Both numerical and experimental results are analyzed to determine the effect of using different orifice sizes on heat transfer rates and flow structure on the target plate. A correlation is obtained for the stagnation Nusselt number as a function of Re and H/D. Optimum heat removal rate are found to occur at H/D=6. According to the experimental results which indicates that orifice diameter and jet velocity are the most effective variables which characterize the heat removal rate, a control system is designed and constructed to vary the orifice diameter in order to control the air flow rate and the plate temperature. Fixing the optimum H/D and for the used blower characteristics the control system is tested and the results show a good response for the control system for different operation conditions so that the cooling rates are increased for the heated plate.