Download or read book An Experimental Investigation of Film Cooling on a Turbine Rotor Blade written by R. P. Dring and published by . This book was released on 1979 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of Air cooled Turbine Blades in Turbojet Engine written by Vernon L. Arne and published by . This book was released on 1951 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of Film Cooling Effectiveness on Gas Turbine Blades written by Shiou-Jiuan Li and published by . This book was released on 2013 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: High turbine inlet temperature becomes necessary for increasing thermal efficiency of modern gas turbines. To prevent failure of turbine components, advance cooling technologies have been applied to different portions of turbine blades. The detailed film cooling effectiveness distributions along a rotor blade has been studied under combined effects of upstream trailing edge unsteady wake with coolant ejection by the pressure sensitive paint (PSP). The experiment is conducted in a low speed wind tunnel with a five blade linear cascade and exit Reynolds number is 370,000. The density ratios for both blade and trailing edge coolant ejection range from 1.5 to 2.0. Blade blowing ratios are 0.5 and 1.0 on suction surface and 1.0 and 2.0 on pressure surface. Trailing edge jet blowing ratio and Strouhal number are 1.0 and 0.12, respectively. Results show the unsteady wake reduces overall effectiveness. However, the unsteady wake with trailing edge coolant ejection enhances overall effectiveness. Results also show that the overall effectiveness increases by using heavier coolant for ejection and blade film cooling. Leading edge film cooling has been investigated using PSP. There are two test models: seven and three-row of film holes for simulating vane and blade, respectively. Four film holes' configurations are used for both models: radial angle cylindrical holes, compound angle cylindrical holes, radial angle shaped holes, and compound angle shaped holes. Density ratios are 1.0 to 2.0 while blowing ratios are 0.5 to 1.5. Experiments were conducted in a low speed wind tunnel with Reynolds number 100,900. The turbulence intensity near test model is about 7%. The results show the shaped holes have overall higher effectiveness than cylindrical holes for both designs. As increasing density ratio, density effect on shaped holes becomes evident. Radial angle holes perform better than compound angle holes as increasing blowing and density ratios. Increasing density ratio generally increases overall effectiveness for all configurations and blowing ratios. One exception occurs for compound angle and radial angle shaped hole of three-row design at lower blowing ratio. Effectiveness along stagnation row reduces as increasing density ratio due to coolant jet with insufficient momentum caused by heavier density coolant, shaped hole, and stagnation row. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148288

Download or read book Experimental Investigation of Film Cooling Effectiveness on Gas Turbine Blades written by Zhihong Gao and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hot gas temperature in gas turbine engines is far above the permissible metal temperatures. Advanced cooling technologies must be applied to cool the blades, so they can withstand the extreme conditions. Film cooling is widely used in modern high temperature and high pressure blades as an active cooling scheme. In this study, the film cooling effectiveness in different regions of gas turbine blades was investigated with various film hole/slot configurations and mainstream flow conditions. The study consisted of four parts: 1) effect of upstream wake on blade surface film cooling, 2) effect of upstream vortex on platform purge flow cooling, 3) influence of hole shape and angle on leading edge film cooling and 4) slot film cooling on trailing edge. Pressure sensitive paint (PSP) technique was used to get the conduction-free film cooling effectiveness distribution. For the blade surface film cooling, the effectiveness from axial shaped holes and compound angle shaped holes were examined. Results showed that the compound angle shaped holes offer better film effectiveness than the axial shaped holes. The upstream stationary wakes have detrimental effect on film effectiveness in certain wake rod phase positions. For platform purge flow cooling, the stator-rotor gap was simulated by a typical labyrinth-like seal. Delta wings were used to generate vortex and modeled the passage vortex generated by the upstream vanes. Results showed that the upstream vortex reduces the film cooling effectiveness on the platform. For the leading edge film cooling, two film cooling designs, each with four film cooling hole configurations, were investigated. Results showed that the shaped holes provide higher film cooling effectiveness than the cylindrical holes at higher average blowing ratios. In the same range of average blowing ratio, the radial angle holes produce better effectiveness than the compound angle holes. The seven-row design results in much higher effectiveness than the three-row design. For the trailing edge slot cooling, the effect of slot lip thickness on film effectiveness under the two mainstream conditions was investigated. Results showed thinner lips offer higher effectiveness. The film effectiveness on the slots reduces when the incoming mainstream boundary layer thickness decreases.

Download or read book Experimental Investigation of Turbine Blade Platform Film Cooling and Rotational Effect on Trailing Edge Internal Cooling written by Lesley Mae Wright and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present work has been an experimental investigation to evaluate the applicability of gas turbine cooling technology. With the temperature of the mainstream gas entering the turbine elevated above the melting temperature of the metal components, these components must be cooled, so they can withstand prolonged exposure to the mainstream gas. Both external and internal cooling techniques have been studied as a means to increase the life of turbine components. Detailed film cooling effectiveness distributions have been obtained on the turbine blade platform with a variety of cooling configurations. Because the newly developed pressure sensitive paint (PSP) technique has proven to be the most suitable technique for measuring the film effectiveness, it was applied to a variety of platform seal configurations and discrete film flows. From the measurements it was shown advanced seals provide more uniform protection through the passage with less potential for ingestion of the hot mainstream gases into the engine cavity. In addition to protecting the outer surface of the turbine components, via film cooling, heat can also be removed from the components internally. Because the turbine blades are rotating within the engine, it is important to consider the effect of rotation on the heat transfer enhancement within the airfoil cooling channels. Through this experimental investigation, the heat transfer enhancement has been measured in narrow, rectangular channels with various turbulators. The present experimental investigation has shown the turbulators, coupled with the rotation induced Coriolis and buoyancy forces, result in non-uniform levels of heat transfer enhancement in the cooling channels. Advanced turbulator configurations can be used to provide increased heat transfer enhancement. Although these designs result in increased frictional losses, the benefit of the heat transfer enhancement outweighs the frictional losses.

Download or read book Experimental Investigation of Air cooled Turbine Blades in Turbojet Engine written by Gordon T. Smith and published by . This book was released on 1951 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Survey of Advantages and Problems Associated with Transpiration Cooling and Film Cooling of Gas turbine Blades written by Ernst Rudolf Georg Eckert and published by . This book was released on 1951 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Transpiration and film cooling promise to be effective methods of cooling gas-turbine blades; consequently, analytical and experimental investigations are being conducted to obtain a better understanding of these processes. This report serves as an introduction to these cooling methods, explains the physical processes, and surveys the information available for predicting blade temperatures and heat-transfer rates. In addition, the difficulties encountered in obtaining a uniform blade temperature are discussed, and the possibilities of correcting these difficulties are indicated. Air is the only coolant considered in the application of these cooling methods.

Download or read book An Experimental Investigation of Heat Transfer to Film cooled Gas turbine Blades written by Tongam H. Loebis and published by . This book was released on 1966 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study of Gas Turbine Blade Film Cooling and Heat Transfer written by Diganta P. Narzary and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern gas turbine engines require higher turbine-entry gas temperature to improve their thermal efficiency and thereby their performance. A major accompanying concern is the heat-up of the turbine components which are already subject to high thermal and mechanical stresses. This heat-up can be reduced by: (i) applying thermal barrier coating (TBC) on the surface, and (ii) providing coolant to the surface by injecting secondary air discharged from the compressor. However, as the bleeding off of compressor discharge air exacts a penalty on engine performance, the cooling functions must be accomplished with the smallest possible secondary air injection. This necessitates a detailed and systematic study of the various flow and geometrical parameters that may have a bearing on the cooling pattern. In the present study, experiments were performed in three regions of a non-rotating gas turbine blade cascade: blade platform, blade span, and blade tip. The blade platform and blade span studies were carried out on a high pressure turbine rotor blade cascade in medium flow conditions. Film-cooling effectiveness or degree of cooling was assessed in terms of cooling hole geometry, blowing ratio, freestream turbulence, coolant-to-mainstream density ratio, purge flow rate, upstream vortex for blade platform cooling and blowing ratio, and upstream vortex for blade span cooling. The blade tip study was performed in a blow-down flow loop in a transonic flow environment. The degree of cooling was assessed in terms of blowing ratio and tip clearance. Limited heat transfer coefficient measurements were also carried out. Mainstream pressure loss was also measured for blade platform and blade tip film-cooling with the help of pitot-static probes. The pressure sensitive paint (PSP) and temperature sensitive paint (TSP) techniques were used for measuring film-cooling effectiveness whereas for heat transfer coefficient measurement, temperature sensitive paint (TSP) technique was employed. Results indicated that the blade platform cooling requires a combination of upstream purge flow and downstream discrete film-cooling holes to cool the entire platform. The shaped cooling holes provided wider film coverage and higher film-cooling effectiveness than the cylindrical holes while also creating lesser mainstream pressure losses. Higher coolant-to-mainstream density ratio resulted in higher effectiveness levels from the cooling holes. On the blade span, at any given blowing ratio, the suction side showed better coolant coverage than the pressure side even though the former had two fewer rows of holes. Film-cooling effectiveness increased with blowing ratio on both sides of the blade. Whereas the pressure side effectiveness continued to increase with blowing ratio, the increase in suction side effectiveness slowed down at higher blowing ratios (M=0.9 and 1.2). Upstream wake had a detrimental effect on film coverage. 0% and 25% wake phase positions significantly decreased film-cooling effectiveness magnitude. Comparison between the compound shaped hole and the compound cylindrical hole design showed higher effectiveness values for shaped holes on the suction side. The cylindrical holes performed marginally better in the curved portion of the pressure side. Finally, the concept tip proved to be better than the baseline tip in terms of reducing mainstream flow leakage and mainstream pressure loss. The film-cooling effectiveness on the concept blade increased with increasing blowing ratio and tip gap. However, the film-coverage on the leading tip portion was almost negligible.

Download or read book An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling written by James D. Heidmann and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Orlando, FL, Jun 2 - Jun 5, 1997.

Download or read book Experimental and Analytical Investigation of Heat transfer Characteristics of a Return flow Air cooled Turbine Rotor Blade written by Francis S. Stepka and published by . This book was released on 1959 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of Advanced Film Cooling Schemes for a Gas Turbine Blade written by Mohamed Gaber Ghorab and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced cooling techniques are essential for further improvement in the efficiency and the power output of gas turbines. Turbine inlet temperatures of 1900 K are typical of current gas turbines, and there is an interest in increasing the temperatures for the next generation of gas turbine engines. Over the past decades, significant effort has been devoted to increase the turbine efficiency and to develop effective cooling strategies to maintain the blade temperature below the melting point of the alloys used to construct the airfoils. As a result, various cooling strategies have been developed such as film, impingement, and muti-pass cooling for the blades, and evaporative cooling for the inlet air. In this work, a state-of-the-art thermal turbomachinery test rig was designed and constructed to investigate the film-cooling performance of advanced film cooling schemes over a flat plate. Designing and constructing mechanical parts, as well developing software codes (Labview and image processing) for transient film cooling measurement was the foremost part of the current experimental work. The thermochromic liquid crystal (TLC) technique was used to measure wall surface temperature. A circular film hole was used to validate the current experimental technique and methodology. The validation results showed that the current experimental technique and methodology were deemed reliable. Subsequently, the film cooling performance of the louver and new hybrid schemes were investigated, experimentally. The louver scheme was proposed by Pratt and Whitney Canada (PWC) to allow the cooling flow to pass through a bend and to encroach an airfoil material (impingement effect), then exit to the outer surface of the airfoil through a designed film hole. Immarigeon and Hassan (2006) then Zhang and Hassan (2006) numerically investigated the film cooling effectiveness performance of the louver scheme. The hybrid scheme was proposed in the current study, which includes two consecutive film hole configurations with interior bending. The cooling performances for the two advanced schemes have been analyzed experimentally over a flat plate across blowing ratios of 0.5, 1.0 and 1.5 at a density ratio of 0.94. The results showed that the louver and the hybrid schemes enhanced the local and the average film cooling performance in terms of film cooling effectiveness, and the net heat flux reductions are better than other published film hole configurations. In addition, both schemes provided an extensively wide spray of 'secondary flow over the outer surface, and thus enhanced the lateral film cooling performance over the downstream surface area. Moreover, the two schemes produced an average heat transfer coefficient ratio near unity at low and high blowing ratios. As a result, the louver and the hybrid schemes are expected to reduce the temperature of the outer surface of the gas turbine airfoil and to provide superior cooling performance, which increases airfoil lifetime. In addition, the adiabatic film cooling performance and flow characteristics for the hybrid scheme were investigated numerically. The numerical investigation was analyzed across blowing ratio, of 0.5, 1, and 2. The flow structures of the hybrid scheme are presented at different blowing ratios to provide a better physical understanding. The results showed that the hybrid scheme directed the secondary flow in the horizontal direction and reduced the jet liftoff at different blowing ratios. Finally, conjugate heat transfer (CHT) and film-cooling analyses were performed to investigate the hybrid scheme performance with different flow configurations. Different geometries of parallel flow and jet impingement with different gap heights as well as the adiabatic case study were investigated at blowing ratios of 0.5 and 1.0. The results showed that the adiabatic case provided downstream centerline superlative cooling performance near the hybrid film hole exit compared to other conjugate geometries studied. At the downstream location, the impingement configuration with a large gap height provided the highest downstream performance at blowing ratio of 0.5 and 1.0 with respect to other cases studied. Moreover, the downstream film cooling performance was enhanced far along the spanwise direction for the CHT cases studied and it has the highest value near the scheme exit for parallel configuration. In addition, the impingement configuration enhanced the upper stream cooling performance compared to parallel flow and it was further enhanced for large gap heights. Keywords: film cooling effectiveness, heat transfer coefficient ratio, louver, hybrid, TLC, NHFR, CHT.

Download or read book Analytical and Experimental Investigation of a Forced convection Air cooled Internal Strut supported Turbine Blade written by Eugene F. Schum and published by . This book was released on 1954 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of Turbine Blade Heat Transfer and Turbine Blade Trailing Edge Cooling written by Jungho Choi and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This experimental study contains two points; part 1 - turbine blade heat transfer under low Reynolds number flow conditions, and part 2 - trailing edge cooling and heat transfer. The effect of unsteady wake and free stream turbulence on heat transfer and pressure coefficients of a turbine blade was investigated in low Reynolds number flows. The experiments were performed on a five blade linear cascade in a low speed wind tunnel. A spoked wheel type wake generator and two different turbulence grids were employed to generate different levels of the Strouhal number and turbulence intensity, respectively. The cascade inlet Reynolds number based on blade chord length was varied from 15,700 to 105,000, and the Strouhal number was varied from 0 to 2.96 by changing the rotating wake passing frequency (rod speed) and cascade inlet velocity. A thin foil thermocouple instrumented blade was used to determine the surface heat transfer coefficient. A Liquid crystal technique based on hue value detection was used to measure the heat transfer coefficient on a trailing edge film cooling model and internal model of a gas turbine blade. It was also used to determine the film effectiveness on the trailing edge. For the internal model, Reynolds numbers based on the hydraulic diameter of the exit slot and exit velocity were 5,000, 10,000, 20,000, and 30,000 and corresponding coolant-to-mainstream velocity ratios were 0.3, 0.6, 1.2, and 1.8 for the external models, respectively. The experiments were performed at two different designs and each design has several different models such as staggered / inline exit, straight / tapered entrance, and smooth / rib entrance. The compressed air was used in coolant air. A circular turbulence grid was employed to upstream in the wind tunnel and square ribs were employed in the inlet chamber to generate turbulence intensity externally and internally, respectively.

Download or read book Experimental Investigation of Air cooled Turbine Blades in Turbojet Engine written by Herman H. Ellerbrock (Jr.) and published by . This book was released on 1951 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Numerical Simulation of Film Cooling on a Turbine Blade Leading edge Model written by Douglas Stenger and published by . This book was released on 2009 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present study is a three-dimensional numerical investigation of the effectiveness of film cooling for a turbine blade leading-edge model with both a single and a three-hole cooling configuration. The model used has the same dimensions as those in the experimental investigation of Ou and Rivir (2006). It consists of a half cylinder with a flat after-body, and well represents the leading edge of a turbine blade. The single coolant hole is situated approximately at the spanwise center of the cylindrical model, and makes an angle of 21.5 degrees to the leading edge and 20 degrees to the spanwise direction. For the three-hole configuration, the center hole is positioned the same as the single hole in the single-hole configuration, with the adjacent holes located at a spanwise distance of 37.4 mm on either side of the center hole. Multi-block grids were generated using GridGen, and the flows were simulated using the flow solver Fluent. A highly clustered structured C-grid was developed around the leading edge of the model. The outer unstructured-grid domain represents the wind tunnel as used in the experimental study of Ou and Rivir (2006), and the leading-edge model is located at the center of the domain. Simulations were carried out for blowing ratios, M, ranging from 0.75 to 2.0. Turbulence was represented using the k-? shear-stress transport (SST) model, and the flow was assumed to have a free-stream turbulence intensity of 0.75%. Two types of boundary conditions were used to represent the blade wall: an adiabatic surface, and a conductive surface. The adiabatic-wall results over-predicted the film-cooling effectiveness in the far downstream region for low blowing ratios. Also, in the vicinity of the cooling hole, an increase in blowing ratio resulted in higher film cooling effectiveness than observed in the experiments. It should be noted that the steady RANS-based turbulence model used under-predicts the interaction between the coolant and mainstream flow near the cooling-pipe exit. The conductive-wall results show a much closer agreement with experimental data for film effectiveness as compared to the adiabatic-wall predictions. Simulations were also performed with higher values of turbulence intensity at the cooling-hole inlet, and these predicted the coolant-mainstream interaction and the film-cooling effectiveness more accurately. Finally, a novel concept of pulsing the coolant flow was implemented so as to achieve film-cooling effectiveness equivalent to that with constant cooling, but with reduced overall coolant air, thereby enhancing turbine efficiency. Pulsed cooling with pulsing frequency PF = 5 and 10Hz, and duty cycle DC = 50%, shows the greatest cooling effects. The three-hole cooling results indicate that the 49 mm spanwise distance used for computing the spanwise-averaged values for film-cooling effectiveness accounts for all of the film-coolant spreading provided by the single hole. Also, the neighboring cooling holes contribute little film cooling to the 49 mm spanwise distance. The most significant new finding in this work is that the inclusion of wall conductance is the main factor responsible for reproducing the experimental data.

Download or read book Experimental Investigation of Air cooled Turbine Blades in Turbojet Engine written by Francis S. Stepka and published by . This book was released on 1954 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: