Nozzle Guide Vane Sweeping Jet Impingement Cooling PDF Download
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Author: Lucas Agricola Publisher: ISBN: Category : Gas-turbines Languages : en Pages : 91
Book Description
Sweeping jet impingement cooling was investigated in a gas turbine nozzle guide vane design with an engine-relevant Biot number of 0.3. Sweeping jets were created with fluidic oscillators and were compared to steady jets produced by cylindrical orifices (with length-to-diameter ratio of 1), the current state-of-the-art in engine designs. Experiments were performed in a low speed linear cascade with additively manufactured test pieces. The impingement cooling geometries were examined at multiple coolant mass flow rates and freestream turbulence intensities. The overall effectiveness of each cooling geometry was calculated using thermocouple measurements of the freestream and coolant temperatures, and infrared thermography measurements of the vane external surface temperature. A computational thermal inertia technique was used to determine the internal Nusselt numbers. The heat transfer provided by steady impinging jets produced a higher overall effectiveness and Nusselt number in the leading edge geometry. The sweeping jets provided more uniform heat transfer, reducing thermal gradients near the stagnation point. Pressure drop across each jet geometry was measured at a range of applicable mass flow rates. Fluidic oscillators were shown to create similar pressure drop to circular orifice holes when additive manufacturing abilities were fully incorporated in the nozzle guide vane internal cooling designs.
Author: Lucas Agricola Publisher: ISBN: Category : Gas-turbines Languages : en Pages : 91
Book Description
Sweeping jet impingement cooling was investigated in a gas turbine nozzle guide vane design with an engine-relevant Biot number of 0.3. Sweeping jets were created with fluidic oscillators and were compared to steady jets produced by cylindrical orifices (with length-to-diameter ratio of 1), the current state-of-the-art in engine designs. Experiments were performed in a low speed linear cascade with additively manufactured test pieces. The impingement cooling geometries were examined at multiple coolant mass flow rates and freestream turbulence intensities. The overall effectiveness of each cooling geometry was calculated using thermocouple measurements of the freestream and coolant temperatures, and infrared thermography measurements of the vane external surface temperature. A computational thermal inertia technique was used to determine the internal Nusselt numbers. The heat transfer provided by steady impinging jets produced a higher overall effectiveness and Nusselt number in the leading edge geometry. The sweeping jets provided more uniform heat transfer, reducing thermal gradients near the stagnation point. Pressure drop across each jet geometry was measured at a range of applicable mass flow rates. Fluidic oscillators were shown to create similar pressure drop to circular orifice holes when additive manufacturing abilities were fully incorporated in the nozzle guide vane internal cooling designs.
Author: Mohammad Arif Hossain Publisher: ISBN: Category : Gas-turbines Languages : en Pages : 242
Book Description
Gas turbine is an integrated part of modern aviation and power generation industry. The thermal efficiency of a gas turbine strongly depends on the turbine inlet temperature (TIT), and the turbine designers are continuously pushing the TIT to a higher value. Due to the increased freedom in additive manufacturing, the complex internal and external geometries of the turbine blade can be leveraged to utilize innovative cooling designs to address some of the shortcomings of current cooling technologies. The sweeping jet film cooling has shown some promise to be an effective method of cooling where the coolant can be brought very close to the blade surface due to its sweeping nature. A series of experiments were performed using a row of fluidic oscillators on a flat plate. Adiabatic cooling effectiveness, convective heat transfer coefficient, thermal field, and discharge coefficient were measured over a range of blowing ratios and freestream turbulence. Results were compared with a conventional shaped hole (777-hole), and the sweeping jet hole shows improved cooling performance in the lateral direction. Numerical simulation also confirmed that the sweeping jet creates two alternating vortices that do not have mutual interaction in time. When the jet sweeps to one side of the hole exit, it acts as a vortex generator as it interacts with the mainstream ow. This prevents the formation of the counter-rotating vortex pair (CRVP) and allows the coolant to spread in the lateral direction. The results obtained from the low speed at plate tests were utilized to design the sweeping jet film cooling hole for more representative turbine vane geometry. Experiments were performed in a low-speed linear cascade facility. Results showed that the sweeping jet hole has higher cooling effectiveness in the near hole region compared to the shaped hole at high blowing ratios. Next, a detailed experimental investigation of sweeping jet film cooling on the suction surface of a near engine scale transonic nozzle guide vane at an engine relevant Mach number (Ma = 0.8) and Reynolds number (Re = 1x10e6) to determine the effect of compressibility. The heat transfer measurements were conducted with a transient IR method, and the convective heat transfer coefficient (HTC) and adiabatic film cooling effectiveness were estimated using a dual linear regression technique (DLRT). Aerodynamic loss measurements were also performed at an exit plane downstream of the vane cascade. Finally, a comprehensive design integration of sweeping jet film hole was carried out in a Direct Metal Laser Sintering (DMLS) enabled engine scale nozzle guide vane and experimental investigation of overall cooling effectiveness at engine relevant temperature conditions were assessed. The systematic evolution of a sweeping jet film cooling hole design from a large scale flat plate to an engine scale nozzle guide vane has been presented.
Author: Dulfharah Nizam Memth Ali Publisher: ISBN: Category : Heat Languages : en Pages : 75
Book Description
This research focused on the study about the effect of nozzle diameter on jet impingement cooling system. The impinging jet can be described as a phenomenon in which the fluid exiting from a nozzle or orifice hits a wall or solid surface usually at normal angle. Impinging air jets have been widely used in many industrial applications in order to achieve enhanced coefficients for convective heating, cooling or drying. A single air jet or arrays of air jets, impinging normally on a surface are an effective method to enhance heat and mass transfer. Engineering applications that widely use air jets include cooling of hot steel plates, tempering of glass plates, drying of textiles and paper, cooling of turbine blades, electronic components and de-icing of aircraft. Experiments were conducted to determine the effect of nozzle diameter on the heat transfer coefficients from a small heat source to a jet impingement cooling system, submerged and confined air. The experiment were carried out with a single jet with three different nozzle diameter, d; 0.5, 1.0, 2.0 cm and four dimensionless jet to heat source spacing, S/d (6, 8, 10, 12) were tested within the laminar jet Reynolds number ranging from 500-2300. The results indicate that the heat transfer coefficient, h increase with the increasing nozzle diameter at the stagnation point region corresponding to 0 r/d
Author: Lucas Agricola
Author: Lucas Agricola
Author: Mohammad Arif Hossain
Author: 
Author: Irene Cresci
Author: G. A. Halls
Author: Dulfharah Nizam Memth Ali
Author: David Japikse
Author: Dave Rowbury
Author: Cheng-Chyuan Lai
Author: M. Pais