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Full-Text Articles in Engineering
Rotational And Shower Head Cooling Hole Effects On Leading-Edge Jet Impingement Heat Transfer, Weston Olson
Rotational And Shower Head Cooling Hole Effects On Leading-Edge Jet Impingement Heat Transfer, Weston Olson
Electronic Theses and Dissertations, 2020-
Jet Impingement and shower head cooling are critical cooling techniques used to maintain turbine blades at operational temperatures. Jet impingement is extremely effective at removing large amounts of heat flux from the target surface, the inner blade wall, through stagnation point heat transfer. Shower head cooling produces a cooling film around the exterior of the blade, in return reducing external heat flux. The current work consisted of investigating the jet impingement effectiveness with rotational effects for two different cooling schemes. The analysis was conducted numerically using STAR CCM+ with two different turbulence models, the three equation Lag Elliptic Blending K …
A Shock Tube Chemical Kinetic Study Of Ethanol Oxidation At Elevated Pressures, Andrew Laich
A Shock Tube Chemical Kinetic Study Of Ethanol Oxidation At Elevated Pressures, Andrew Laich
Electronic Theses and Dissertations, 2020-
Understanding the combustion chemistry of ethanol is critical for continued proliferation and use in future internal combustion engines (ICEs) that will operate in a downsized, turbo-charged, high compression configuration. Detailed chemical kinetic reaction mechanisms already exist for ethanol, which have been validated over a range of operating conditions; however, capturing the conditions that may be seen in future ICEs requires extension of these conditions, namely at elevated pressure. Investigating the kinetics of ethanol existing in a combustion system first involve, for example, understanding a key global metric like ignition delay time (IDT) and measuring major or minor species in a …
High-Speed Imaging Of Reflected Shockwave-Initiated Combustion, Erik Ninnemann
High-Speed Imaging Of Reflected Shockwave-Initiated Combustion, Erik Ninnemann
Electronic Theses and Dissertations, 2020-
Shock tubes are considered ideal reactors and are used extensively to provide valuable chemical kinetic measurements, such as ignition delay times and in-situ species time-histories. However, due to nonideal affects the combustion of fuel inside shock tubes can become nonhomogeneous, particularly at low temperatures, which complicates the acquired data. In this work, the combustion of practical fuels used by society are investigated with high-speed imaging. First, high-speed images were captured through the end wall of the shock tube for two hydrogen-oxygen systems. The combustion process was found to initiate in two modes, one that is homogeneous across the fluid medium …
Detailed Study Of Flow And Surface Heat Transfer Enhancement Mechanism In The Presence Of Dimples And/Or Protrusions, Gaurav Gupta
Detailed Study Of Flow And Surface Heat Transfer Enhancement Mechanism In The Presence Of Dimples And/Or Protrusions, Gaurav Gupta
Electronic Theses and Dissertations, 2020-
Recent advancements in material technology have led to the development of non-porous negative Poisson's ratio (NPR) materials (also called auxetic structures) by making spherical inline dimples on both sides of an elastic sheet. Manufacturing technologies such as 3-D printing and additive manufacturing paved the way to realize the complex shapes needed to achieve NPR behavior. These materials are desirable in many engineering applications, especially in the gas turbines hot-gas-path, due to their unique properties. In the current study, an effort is made to understand the flow physics and surface heat transfer mechanism for channel flow having one wall with spherical …
Tip Clearance Effect On Convective Heat Transfer In Micro Scale Pin Fins, Hanieh Tabkhivayghan
Tip Clearance Effect On Convective Heat Transfer In Micro Scale Pin Fins, Hanieh Tabkhivayghan
Electronic Theses and Dissertations, 2020-
Fluid flow and local heat transfer in a microchannel with single and array of pin fins have been studied. For the single pin fin case, a microchannel with a 150-µm diameter pin fin with a tip clearance was experimentally and numerically studied for three Reynolds numbers in laminar regime. Tip clearances of 0, 30, 45 and 100 µm in a 200-µm high microchannel. Experimental and numerical local temperatures and the corresponding Nusselt numbers along the centerline of the pin fin were presented and discussed. Local temperatures were measured on top of the heater surface and downstream the pin fin through …