Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Discharge coefficient

Experimental Study of Heat Transfer Parameters of Impingement Heating System Represented by Conductive Target Plate of Resistive film

Assim H. Yousif; Amer M. Al Dabagh; Salah H. Abid Aun

Engineering and Technology Journal, 2016, Volume 34, Issue 8, Pages 1588-1604
DOI: 10.30684/etj.34.8A.10

The current experimental study focuses on the heat transfer characteristics and pressure losses for impingement systemwhich is used in cooling the liner of gas turbine combustor. Recent experiment method of conductive heat transfer technique with resistive film in the back side target plate is introduced. The present experimental model measured both the heat transfer coefficient for inner target surface and the wall cooling effectiveness for outer target surface. To physically explain the phenomena associated with interaction flow area, a computational fluid dynamic code (Fluent 14) is employed. The continuity, momentum and energy equations arecomputationally solved to analyze the flow field in the jet impingement area. The tests models of the impingement plate are made from round jet holes of inline and staggered arrays arrangement with jet to jet spacing of four-hole diameter. Jet Reynolds numbers of 4200 to 15000 and jet height to diameter ratio of 1.5, 2.0, and 3.0 are maintained. The inline array, as expected enhanced the wall cooling effectiveness over that of the staggered array by10.3%andboth jet spacing and Reynolds number have an evident effect on the discharge coefficient. Empirical correlations are obtained for both arrays arrangement to predict the area-averaged Nusselt number as a function of jet governing parameters.

Analysis of Hydraulic Characteristics of Broad Crested Weir with Semicircle Control Section

Thabet mohammed abdulatif

Engineering and Technology Journal, 2016, Volume 34, Issue 1, Pages 123-135
DOI: 10.30684/etj.34.1A.11

This study deals with evaluation ofthe hydraulic characteristics such as critical depth, and discharge coefficient of a broad crested weir with semi-circle control section extend across the full width of a laboratory channel. Provided the occurrence of critical Flow at the control section, the use of solver function in Microsoft Excel replaces the traditional methods such as trial and error method and chart to solve governing equations represent the hydraulic condition at the control section. The use of solver function provides accurate solution of critical depthsfor different flowrates ranges, knowing these depths valuesmake it easy for computation of theoretical discharges. Data obtained from laboratory experiments provide information on head – discharge relationship examined under free flow condition. The (HEC-RAS)software version 4.1 was developed with steady flow state yields, water surface profiles, and plot cross sections and computational of rating curve. The results achieved are compared with the observations show acceptable agreement between these two results and the flow remains critical, not supercritical along the weir crest. The study shows that theoretical discharge equation is a function of shape factor, the laboratory discharge measurement varies with the square head upstream weir crest, and the values of the discharge coefficient are not quite constant with the range of modular limit, but increases slightly with increasing discharge.