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Introduction to Engineering is the first engineering course American University in Cairo students take upon admission to the engineering program. It is required of students in all disciplines of engineering. It is a one-credit-hour course that covers topics including history of engineering, engineering fields of specializations, the engineering profession, engineering communications, engineering ethics, and societal obligations. Community-based learning (CBL) was introduced into the course via the required course project. The project was to design toys for children at a school in a disadvantaged squatter community in Old Cairo, Egypt, where infrastructure is poor and education and social mobility can be very limited. The project was carried out in partnership with a non-governmental organization based in Old Cairo. This paper shows how the introductory engineering course was redesigned to integrate CBL while meeting the stated ABET course outcomes. Included are detailed instructions on the tools and structure of the project to provide an example for others wishing to adapt some of these tools to other courses. The paper presents the outcome assessments and survey results to evaluate the project’s success at meeting the stated outcomes and includes a discussion on the benefits to the students and the community partner. [ABSTRACT FROM AUTHOR]

Film cooling is used in a wide range of industrial and engineering applications; one of the most important is in gas turbine cooling. The intent of film cooling is to provide a layer of cool film between the surface and the hot gas. Predicting film-cooling characteristics, particularly at high blowing ratios where the film is likely to be detached from the surface, is a challenge due to the complex three-dimensional and possibly anisotropic nature of the flow. Despite the growth of more sophisticated techniques for modeling turbulence, such as large eddy simulation (LES), the most commonly used methods in design are Reynolds-Averaged Navier Stokes (RANS) methods that employ a two-equation turbulence model for specifying the eddy viscosity. Although these models have deficiencies, they continue to be used throughout industry because they offer reasonable turnaround time as compared to LES or other methods. This paper studies in detail two cases, one of high blowing ratio (off-design condition) of 2.0 and low blowing ratio of 0.5, and compares RANS-based computational fluid dynamics (CFD) results with experimental data for flow field temperatures and centerline, lateral, and span-averaged film effectiveness for a 35-degree circular jet. The effects of mainstream turbulence conditions, boundary layer thickness, and numerical dissipation are evaluated and found to have minimal impact in the wake region of separated films (i.e., they cannot account for the discrepancy between measured and predicted CFD results in the wake region). Analyses of low blowing ratio cases are in good agreement with data; however, there are some smaller discrepancies, particularly in lateral spreading of the jet. [ABSTRACT FROM PUBLISHER]

To increase the thermal efficiency of gas turbines, inlet temperature of gas is increased. This results in the requirement of cooling of gas turbine blades and vanes. Internal cooling of gas turbine blades and vanes is one of several options. Two-pass channels are provided with ribs to enhance heat transfer at the expense of an increased pressure drop. The space in the blade is limited and requires channels with small aspect ratios. Numerical simulations have been performed to investigate heat transfer, flow field and pressure loss in a two-pass channel equipped with 45° ribs with aspect ratio (W/H) equal to 1:3 in the inlet pass and 1:1 in the outlet pass with both connected together with a 180° bend. The results are compared with a higher aspect ratio channel (W/H = 1:2, inlet pass). In the ribbed channel, a decrease in pressure drop was observed with a decrease in the aspect ratio of the channel. The smaller aspect ratio channel not only allows using more cooling channels in the blade, but also results in more heat transfer enhancement. The divider-to-tip wall distance (W) has influence on the pressure drop, as well as on the heat transfer enhancement at the bend and outlet pass. Heat transfer decreases with decrease in aspect ratio of the inlet pass of the two-pass channel. With increase in divider-to-tip wall distance, heat transfer tries to attain a constant value. [ABSTRACT FROM AUTHOR]

Two-pass channels are used for internal cooling in a number of engineering systems e.g., gas turbines. Fluid travelling through the curved path, experiences pressure and centrifugal forces, that result in pressure driven secondary motion. This motion helps in moving the cold high momentum fluid from the channel core to the side walls and plays a significant role in the heat transfer in the channel bend and outlet pass. The present study investigates using Computational Fluid Dynamics (CFD), the flow structure, heat transfer enhancement and pressure drop in a smooth channel with varying aspect ratio channel at different divider-to-tip wall distances. Numerical simulations are performed in two-pass smooth channel with aspect ratio W/H = 1:3 at inlet pass and W/H = 1:1 at outlet pass for a variety of divider-to-tip wall distances. The results show that with a decrease in aspect ratio of inlet pass of the channel, pressure loss decreases. The divider-to-tip wall distance (W) not only influences the pressure drop, but also the heat transfer enhancement at the bend and outlet pass. With an increase in the divider-to-tip wall distance, the areas of enhanced heat transfer shifts from side walls of outlet pass towards the inlet pass. To compromise between heat transfer and pressure drop in the channel, W/H = 0.88 is found to be optimum for the channel under study. [ABSTRACT FROM AUTHOR]

A small-scale concentrated solar power (CSP) unit was designed to provide electricity and hot water using an organic Rankine cycle (ORC) for Egypt as part of an undergraduate capstone project. The system was designed for a target power output of 3 kW. It uses parabolic troughs to heat ethylene glycol used as the heat transfer fluid, which absorbs heat in the trough collector and transfers it to the working fluid through a heat exchanger. The system consists of 9 parabolic troughs and a total aperture area of 67 m2, providing the required 3 kW of energy to the ORC. One parabolic trough was manufactured to test its thermal efficiency according to ASHRAE standard 93-2003 [Methods of Testing to Determine the Thermal Performance of Solar Collectors (ASHRAE, Inc., 1791 Tullie Circle, NE, Atlanta, GA 30329, 2003)] and compared it to its calculated value. A simple microcontroller-based system was used to track the sun. [ABSTRACT FROM AUTHOR]

Computational fluid dynamics models are used to predict the heat transfer distribution on a smooth surface under an array of angled impinging jets. The three-dimensional numerical models simulate impingement with cross flow in one direction. Jet angle is varied between 30°, 60°, and 90° as measured from the smooth flat impingement surface. Conjugate conduction in the heated boundary is included in the analysis. Two turbulence models are examined, the standard k–e model and the Yang-Shih model. Local and average heat transfer coefficients are compared with test data for 30 test cases. The Yang-Shih model was able to predict average Nusselt number within 2–30%. The standard k–e model predicts average Nusselt number with 0 to nearly 60% error. [ABSTRACT FROM AUTHOR]