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Academic literature on the topic 'Leading edge contamination'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Leading edge contamination"

1

Sengupta, T. K., V. Chaturvedi, P. Kumar, and S. De. "Computation of leading-edge contamination." Computers & Fluids 33, no. 7 (August 2004): 927–51. http://dx.doi.org/10.1016/j.compfluid.2003.07.006.

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Shimazaki, Ayako, Hiroki Sakurai, Masao Iwase, Reiko Yoshimura, and Tsukasa Tada. "Metallic Contamination Control in Leading-Edge ULSI Manufacturing." Solid State Phenomena 145-146 (January 2009): 115–21. http://dx.doi.org/10.4028/www.scientific.net/ssp.145-146.115.

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Contamination control has become a high-centered issue for the fabrication yield, performance and reliability of leading-edge ULSI devices. With the progress of sizing down dimensions in higher-density devices, complicated device structures and various novel electronic materials have been introduced, particularly in the latest devices such as CMOS and nonvolatile memory LSIs (Table I). On the other hand, high productivity is a necessity when you consider QTAT (quick turnaround time) and cost-effective flexible ULSI manufacturing lines. Therefore, effective contamination control coupled with adequate protocol has become essential in such production lines. The point of the protocol is minimization of damage caused by impurity metals diffused from these novel electronic materials [1-5].
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Arnal, D., J. C. Juillen, J. Reneaux, and G. Gasparian. "Effect of wall suction on leading edge contamination." Aerospace Science and Technology 1, no. 8 (December 1997): 505–17. http://dx.doi.org/10.1016/s1270-9638(97)90000-6.

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Wong, P. W. C., M. Maina, and A. M. Cobbin. "Transition and separation control in the leading edge region." Aeronautical Journal 105, no. 1049 (July 2001): 371–78. http://dx.doi.org/10.1017/s0001924000012288.

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Abstract This paper describes an investigation of methods of controlling transition and separation in the leading edge region of military aircraft wings. For wings with the high leading edge sweep relevant to some military aircraft, if attachment line contamination can be prevented then transition is predominantly caused by crossflow instability close to the leading edge. The use of surface suction or cooling for suppressing these instabilities in order to delay transition, has been investigated in a parametric study. The placing of a short suction panel close to the leading edge has been found to be an effective means of controlling instability. Conversely, the level of cooling required to suppress crossflow instability may be too high for practical aircraft applications. The use of suction for preventing laminar separation for pressure distributions with a leading edge suction peak has also been included in the parametric study. The suction quantity required is strongly dependent on the peak height. The suction quantity that can be achieved in practice will limit the maximum peak height that can be attained without laminar separation. An investigation of leading edge stall and control has also been carried out. The analysis suggests that it is important to be able to identify whether the stall is due to laminar bubble bursting or turbulent re-separation, since different methods of controlling the stall may be required.
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Adi Nugraha, Bryan, Joni Kasmara, and Gaguk Marausna. "ANALISIS HEAT TRANSFER ANTI ICING DEVICE SEBAGAI PEMANAS LEADING EDGE WING DENGAN MEMANFAATKAN PANAS GAS BUANG DARI ENGINE." Teknika STTKD: Jurnal Teknik, Elektronik, Engine 6, no. 2 (December 30, 2020): 60–67. http://dx.doi.org/10.56521/teknika.v6i2.212.

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Apabila terjadinya airfoil contaminating berupa icing atau penumpukan partikel es pada leading edge wing dapat menimbulkan hilangnya produksi gaya angkat pada pada sayap pesawat yang dikarenakan faktor cuaca dan kelembaban pada ketinggian tertentu. Untuk mencegah terjadinya icing, yaitu dengan menggunakan anti icing device guna mencegah terjadinya icing. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh geometri pada rasio diameter coil terhadap performa alat heater yang menggunakan panas gas buang engine dan pengaruh geometri heater terhadap efektivitas heater dalam memanaskan airfoil contamination pada leading edge wing. Penelitian ini menggunakan engine genset 1 silinder berkapasitas 2000 Watt dengan variasi beban menggunakan lampu pijar dengan total beban 500 Watt serta menggunakan profil airfoil yang dikondisikan. Hasil penelitian menunjukkan bahwa perubahan geometri coil akan mempengaruhi parameter performa dari alat heater. Parameter performa heater meningkat dengan semakin kecilnya rasio diameter coil. Pemanasan yang memanfaatkan limbah panas gas buang engine dengan menggunakan alat heater helical coil tube feedback memberikan peningkatan performa dan efektivitas dalam melakukan pamanasan leading edge wing dalam mencegah terjadinya kontaminasi. Maka kesimpulan dari penelitian ini menunjukkan bahwa penngunaan alat heater helical coil tube feedback dengan rasio diameter terkecil adalah yang terbaik dalam meningkatkan parameter performa dan efektivitas heater.
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Prasetyo, Danang, Gaguk Marausna, and Joni Kasmara. "STUDI EKSPERIMENTAL PERFORMA ANTI-ICING PICCOLO TUBE WITH TWISTED DENGAN MEMANFAATKAN THERMAL GAS BUANG DARI ENGINE." Teknika STTKD: Jurnal Teknik, Elektronik, Engine 7, no. 1 (July 30, 2021): 1–9. http://dx.doi.org/10.56521/teknika.v7i1.253.

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Hilangnya gaya angkat pada pesawat bisa terjadi karena airfoil contamination berupa icing atau penumpukan partikel es pada leading edge wing yang dikarenakan faktor cuaca dan kelembaban pada ketinggian tertentu. Untuk mencegah terjadinya icing, yaitu dengan menggunakan anti icing guna mencegah terjadinya icing. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh geometri pada rasio diameter tube yang diberi hole terhadap performa heater yang memanfaatkan panas gas buang dari engine dan pengaruh geometri heater terhadap efisiensi heater dalam mencegah terjadinya airfoil contamination pada leading edge wing. Penelitian ini menggunakan engine genset 1 silinder berkapasitas 2000 W dengan variasi beban menggunakan lampu pijar dengan total beban 500 W serta menggunakan profil wing yang dikondisikan. Perubahan geometri twist pada heater dengan penambahan hole dapat menciptakan aliran turbulen, meningkatkan proses perpindahan kalor, dan meningkatkan koefisien perpindahan kalor konveksi pada tube. Dari tiga geometri twist ratio 1.5, 2.27, 2.45 yang paling baik dalam melepaskan kalor yaitu twist ratio 2.45 dengan nilai perpindahan kalor konveksi pada beban rata-rata terbesar.Kesimpulan dari penelitian ini menunjukkan bahwa penggunaan alat berupa piccolo tube with twisted dengan rasio diameter terbesar adalah yang terbaik dalam meningkatkan parameter performa dan efisiensi heater. Perubahan geometri twist akan mempengaruhi efisiensi dari heater.
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Kasmara, Joni, and Gaguk Marausna. "Investigasi Eksperimental Anti-Icing System dengan Memanfaatkan Kalor Dari Gas Buang Engine Pesawat Terbang." Teknika STTKD: Jurnal Teknik, Elektronik, Engine 6, no. 1 (July 31, 2020): 40–48. http://dx.doi.org/10.56521/teknika.v6i1.196.

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Aviation is a high-risk business field. Safety aspects are a top priority to prevent material and non-material losses due to hazards that arise during the flight phase.The stall is one example of a danger that occurs due to the failure of the wing to produce lift.The stall is affected by changes in the wings shape, particularly at the leading edge due to contamination.Contamination occurs in the form of ice particles on the leading edge and regenerates the airflow passing through the wing into turbulent flow.An anti-icing device is needed to overcome this contamination problem by utilizing engine exhaust gas to reduce the consumption of electrical power used in the heating system for the leading edge.Anti-icing design with the helical coil as the main component of the heat exchanger.An experimental method is using to study the effect of the coil diameter ratio on heat transfer characteristics and heat exchanger efficiency.The results showed that the coil diameter ratio affects increasing the secondary flow intensity, creates turbulence flow, increases the heat transfer coefficient, the performance parameters of the heater.
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Obara, Clifford J., and C. P. van Dam. "Keel Design for Low Viscous Drag." Journal of Ship Research 33, no. 02 (June 1, 1989): 145–55. http://dx.doi.org/10.5957/jsr.1989.33.2.145.

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Foil and planform parameters which govern the level of viscous drag produced by the keel of a sailing yacht are discussed. It is shown that the application of laminar boundary-layer flow offers great potential for increased boat speed resulting from the reduction in viscous drag. Three foil shapes have been designed and it is shown that their hydrodynamic characteristics are very much dependent on location and mode of boundary-layer transition. The planform parameter which strongly affects the capabilities of the keel to achieve laminar flow is leading-edge sweep angle. The two significant phenomena related to keel sweep angle which can cause premature transition of the laminar boundary layer are crossflow instability and turbulent contamination of the leading-edge attachment line. These flow phenomena and methods to control them are discussed in detail. The remaining factors that affect the maintainability of laminar flow include surface roughness, surface waviness, and freestream turbulence. Recommended limits for these factors are given to insure achievability of laminar flow on the keel. In addition, the application of a simple trailing-edge flap to improve the hydrodynamic characteristics of a foil at moderate-to-high leeway angles is studied.
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Hong, Zhiheng, Jungang Yang, Shanwei Liu, Yongjun Jia, Chenqing Fan, and Wei Cui. "Coastal Waveform Retracking for HY-2B Altimeter Data by Determining the Effective Trailing Edge and the Low Noise Leading Edge." Remote Sensing 14, no. 19 (October 9, 2022): 5026. http://dx.doi.org/10.3390/rs14195026.

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As an important remote sensing technology, satellite altimetry provides a large amount of observations of sea surface height over the global ocean. In coastal areas, the accuracy of satellite altimetry data decreases greatly due to issues arise in the vicinity of land, related to poorer geophysical corrections and artifacts in the altimeter reflected signals linked to the presence of land within the instrument footprint. To improve the application of HY-2B altimetry data in coastal areas, this study proposes a coastal waveform retracking strategy for HY-2B altimetry mission, which depends on the effective trailing edge and the leading edge, which are less affected by coastal ‘contamination’, to retrieve accurate waveform information. The HY-2B pass 323 and pass 196 data are reprocessed, and the accuracy of the reprocessing results in the range of 0–40 km offshore is validated against the tide gauge data and compared with the HY-2B standard SGDR data. According to the analysis conclusion, the accuracy of the reprocessed data is higher than that of the SGDR data and has good performance within 15 km offshore. For the pass 323, the mean value of correlation coefficient and RMS of the reprocessed data against the corresponding tide gauge data are 0.893 and 45.1 cm, respectively, in the range within 0–15 km offshore, and are 0.86 and 33.6 cm, respectively, in the range beyond 15 km offshore. For the pass 196, the mean value of correlation coefficient and RMS of the reprocessed data against the corresponding tide gauge data in the range within 0–12 km offshore are 0.84 and 33.0 cm, respectively, and in the range within 0–5 km offshore to the island are 0.90 and 29.3 cm, respectively, and in the range beyond 5 km offshore to the island are 0.92 and 36.2 cm, respectively, which are all better than the corresponding values of the SGDR data, especially in the range closed to the land. The results indicate that the proposed coastal waveform retracking strategy for HY-2B altimetry greatly improves the quality of HY-2B altimetry data in coastal areas.
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Anand, Avnika Singh, Dipti Prasad, Amitabh Mr, Shashi Bala Singh, and Ekta Kohli. "Food Nanotechnologies: Purchasing a Double Edge Sword." Defence Life Science Journal 3, no. 3 (June 25, 2018): 277. http://dx.doi.org/10.14429/dlsj.3.12922.

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<p>Rapid development of nanotechnology has revolutionsed various areas of conventional food science and food industry. The novel properties of nanoparticles (NPs) have led to increasing application of nanotechnology in food industry. Nanofood market have a variety of products like the creamy ice-cream, drinks with no fat, enhanced flavour with nutrients and better textured, coloured and fresh looking food. Continuous monitoring for food spoilage or contamination is possible too. Nanotechnology has transformed the food industries which claim health benefits along with better taste. With the increasing use of NPs especially in food products, where humans are in close contact of the engineered nanomaterials (NMs), it is important to ensure safety before use. Bio-nano interactions often result in novel reaction and formation of products leading to toxicity. NPs mediated toxicity mainly includes inflammation, oxidative damage and genotoxicity. Prolong use of these particles can cause detrimental effects on health. Presently, due to lack of appropriate guidelines and regulations for food nanotechnology there are uncertainties regarding risk identification. Hence, it is essential to evaluate the consequences of this technology in terms of general public and occupational health risks associated with the manufacture, use and disposal of NMs, before instigating the same in day to day use.</p>
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Books on the topic "Leading edge contamination"

1

Development of three-dimensional flow code package to predict performance and stability of aircraft with leading edge ice contamination. [Washington, DC: National Aeronautics and Space Administration, 1996.

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M, Summa J., and United States. National Aeronautics and Space Administration., eds. Development of three-dimensional flow code package to predict performance and stability of aircraft with leading edge ice contamination. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Development of three-dimensional flow code package to predict performance and stability of aircraft with leading edge ice contamination. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Development of three-dimensional flow code package to predict performance and stability of aircraft with leading edge ice contamination. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Book chapters on the topic "Leading edge contamination"

1

Arnal, D., and J. C. Juillen. "Leading-Edge Contamination and Relaminarization on a Swept Wing at Incidence." In Numerical and Physical Aspects of Aerodynamic Flows IV, 391–402. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-662-02643-4_25.

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Juillen, J. C., and D. Arnal. "Experimental Study of Boundary Layer Suction Effects on Leading Edge Contamination along the Attachment Line of a Swept Wing." In Laminar-Turbulent Transition, 173–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-79765-1_20.

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Hoddeson, Lillian, and Peter Garrett. "Solar Energy: Working at the Edge of Feasibility (1979–2007)." In The Man Who Saw Tomorrow, 171–86. The MIT Press, 2018. http://dx.doi.org/10.7551/mitpress/9780262037532.003.0009.

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Ovshinsky was not the inventor of thin-film amorphous silicon solar cells, but under his direction ECD greatly improved their efficiency and dramatically lowered their cost through Ovshinsky’s invention of a system for mass-producing the cells “roll-to-roll” in a continuous process. While Ovshinsky conceived of this process, it was the job of his talented staff to solve the incredibly challenging engineering problems involved in roll-coating the multi-layered solar panels without cross-contamination. Over nearly three decades, ECD scientists built a series of progressively larger solar cell production machines delivering higher and higher annual power wattage (eventually 30 megawatts), drawing on support first from ARCO and later from Sohio, Sharp, Canon, Sovlux, and Bekaert. ECD’s United Solar division eventually became the leading US producer of thin-film solar panels.
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Conference papers on the topic "Leading edge contamination"

1

Katiyar, S., and S. Sarkar. "Leading Edge Contamination of a C-D Compressor Blade Using Large Eddy Simulation." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14192.

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Abstract A large-eddy simulation (LES) is employed here to predict the flow field over the suction surface of a controlled-diffusion (C-D) compressor stator blade following the experiment of Hobson et al. [1]. When compared with the experiment, LES depicts a separation bubble (SB) in the mid-chord region of the suction surface, although discrepancies exist in Cp. Further, the LES resolves the growth of boundary layer over the mid-chord and levels of turbulence intensity with an acceptable limit. What is noteworthy that LES also resolves a tiny SB near the leading-edge at the designed inflow angle of 38.3°. The objective of the present study is to assess how this leading-edge bubble influences the transition and development of boundary layer on the suction surface before the mid-chord. It appears that the separation at leading-edge suddenly enhances the perturbation levels exciting development of boundary layer downstream. The boundary layer becomes pre-transitional followed by a decay of fluctuations up to 30% of chord attributing to the local flow acceleration. Further, the boundary layer appears like laminar after being relaxed from the leading edge excitation near the mid-chord. It separates again because of the adverse pressure gradient, depicting augmentation of turbulence followed by the breakdown at about 70% of chord.
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Tanner, Clinton E. "The Effect of Wing Leading Edge Contamination on the Stall Characteristics of Aircraft." In 2007 SAE Aircraft and Engine Icing International Conference. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2007. http://dx.doi.org/10.4271/2007-01-3286.

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Diab, Aya, Moataz Alaa, Ahmed Hossam El-Din, Hassan Salem, and Zakaria Ghoneim. "Performance Degradation of Wind Turbine Airfoils due to Dust Contamination: A Comparative Numerical Study." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-44012.

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Sand accumulation can pose significant problems to wind turbines operating in the dusty Saharan environments of the Middle East and North Africa. Despite its difficulty, sand particles can be to a great extent avoided using sealed power drive trains; however, surface contamination of the blades is certainly unavoidable. As a result, aerodynamic losses and even premature separation can be incurred. To mitigate such advert consequences and avoid significant power losses, the choice of properly designed airfoil sections with low contamination sensitivity is a must. Alternatively, mitigation techniques for premature separation may also be considered. In this paper the contamination sensitivity of a number of airfoil sections widely used in the wind turbine industry is compared. Additionally, the possibility of deploying a leading edge slat to mitigate the contamination-driven performance degradation of wind turbine airfoils is explored. A two dimensional CFD model of the particle laden flow over an airfoil section is developed by solving Navier-Stokes equations along with the SST k-ω turbulence model. Additionally, a particle deposition model has been deployed via FLUENT’s discrete phase modeling capability to simulate dust particles trajectories and hence predict their accumulation rate. The preliminary results obtained indicate that airfoil sections with low surface contamination sensitivity specifically designed for wind turbines perform better under dusty conditions. Furthermore installing a leading edge slat affects the aerodynamics of the particle laden flow and may therefore be used to mitigate the adverse effects of surface contamination that otherwise would require frequent cleaning which can be expensive.
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Riddle Vogt, Sarah, and Cristian Landoni. "Monitoring acidic and basic molecular contamination in leading edge lithography and metrology applications: quantitative comparison of solid state and impinger-based sampling methods." In SPIE Advanced Lithography, edited by Christopher J. Raymond. SPIE, 2010. http://dx.doi.org/10.1117/12.846364.

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Zhu, David, Soh Ping Neo, Alfred Quah, Ghim Boon Ang, Lei Zhu, Yanhua Huang, Hong Tak Koo, Moi Kian Yau, Ma Hninhnin, and Nagalingam Dayanand. "A Systematic Failure Analysis to Reveal the Mystery of Lower N-Well Resistance." In ISTFA 2011. ASM International, 2011. http://dx.doi.org/10.31399/asm.cp.istfa2011p0185.

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Abstract In this paper, we will describe a low yield case which revealed itself as leakage failures near the wafer edge. A systematic problem solving approach was used based on the application of a variety of FA techniques such as electrical curve tracing, Spreading Resistance Probing (SRP), Secondary Ion Mass Spectrometry (SIMS), and Chemical Analysis coupled with extensive Fab investigations. These techniques transformed an invisible defect into a visible one, leading to a full resolution of the issue with good understanding of the failure mechanism and the root cause. We will show that the wafer edge leakage was the result of N-type contamination of the substrate due to Phosphorus outgassing from the V-ring during the high temperature Argon anneal process.
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Lietmeyer, Christoph, Karsten Oehlert, and Joerg R. Seume. "Optimal Application of Riblets on Compressor Blades and Their Contamination Behavior." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46855.

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During the last decades, riblets have shown a potential for viscous drag reduction in turbulent boundary layers. Several investigations and measurements of skin-friction in the boundary layer over flat plates and on turbomachinery type blades with ideal riblet geometry have been reported in the literature. The question where riblets must be applied on the surface of a compressor blade is still not sufficiently answered. In a first step, the profile loss reduction by ideal triangular riblets with a trapezoidal groove and a constant geometry along the surface on the suction and pressure side of a compressor blade is investigated. The results show a higher potential on the profile loss reduction by riblets on the suction side. In a second step, the effect of laser-structured ribs on the laminar separation bubble and the influence of these structures on the laminar boundary layer near the leading edge are investigated. After clarifying the best choices where riblets should be applied on the blade surface, a strategy for locally adapted riblets is presented. The suction side of a compressor blade is laser-structured with a segmented riblet-like structure with a constant geometry in each segment. The measured profile loss reduction shows the increasing effect on the profile loss reduction of this locally adapted structure compared to a constant riblet-geometry along the surface. Furthermore, the particle deposition on a riblet-structured compressor blade is investigated and compared to the particle deposition on a smooth surface. Results show a primary particle deposition on the riblet tips followed by an agglomeration. The particle deposition on the smooth surface is stochastic.
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Obara, Clifford J., and C. P. van Dam. "Keel Design for Low Viscous Drag." In SNAME 8th Chesapeake Sailing Yacht Symposium. SNAME, 1987. http://dx.doi.org/10.5957/csys-1987-006.

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In this paper, foil and planform parameters which govern the level of viscous drag produced by the keel of a sailing yacht are discussed. It is shown that the application of laminar boundary-Layer flow offers great potential for increased boat speed resulting from the reduction in viscous drag. Three foil shapes have been designed and it is shown that their hydro­dynamic characteristics are very much dependent on location and mode of boundary-Layer transition. The planform parameter which strongly affects the capabilities of the keel to achieve laminar flow is lea ding-edge sweep angle. The two significant phenomena related to keel sweep angle which can cause premature transition of the laminar boundary layer are crossflow instability and turbulent contamination of the leading-edge attachment line. These flow phenomena and methods to control them are discussed in detail. The remaining factors that affect the maintainability of laminar flow include surface roughness, surface waviness, and freestream turbulence. Recommended limits for these factors are given to insure achievability of laminar flow on the keel. In addition, the application of a simple trailing-edge flap to improve the hydrodynamic characteristics of a foil at moderate-to-high leeway angles is studied.
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8

Yu, Xue, and Liu Yan. "High Humidity Aerodynamic Effects Study on Offshore Wind Turbine Airfoil/Blade Performance Through CFD Analysis." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63129.

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Damp air with high humidity combined with foggy, rainy weather as well as icing in winter weather often found to cause turbine performance degradation, and it is more concerned with off-shore wind farm development. To address and understand the high humidity effects on wind turbine performance, our study has been conducted with spread sheet analysis on damp air properties investigation for air density and viscosity, then CFD modeling study using Fluent were carried out on Airfoil and Blade aerodynamic performance effects investigation due to water vapor partial pressure of mixing flow and water condensation around leading edge and trailing edge of airfoil. It is found that the high humidity effects with water vapor mixing flow and water condensation thin film around airfoil may have insignificant effect directly on airfoil/blade performance; however the indirect effects such as blade contamination and icing due to the water condensation may have significant effects on turbine performance degradation. Also found the foggy weather with micro water droplet (including rainy weather) may cause higher drag that lead to turbine performance degradation. It is found that at high temperature, the high humidity effect on air density cannot be ignored for annual energy production calculation. As qualitative validation, the CFD result was compared and correlated with field observation in foggy day of cold weather. The blade contamination and icing phenomenon need to be further investigated in the future study, and blade surface properties such as high surface energy coating effects on water condensation and icing will be investigated for anti-icing coating agent development.
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Gartshore, Ian S., Marthe Salcudean, Y. Barnea, K. Zhang, and F. Aghadsi. "Some Effects of Coolant Density on Film Cooling Effectiveness." In ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-076.

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Experiments have been conducted on a large wind tunnel model of the leading edge region of a turbine blade. The model had a semi-circular leading edge in which four rows of holes were symmetrically placed about the stagnation line, two at ±15° and two at ±44°. Air and alternatively CO2 were injected from the coolant holes after contamination with a known small percentage of propane. Using a flame ionization detector and the mass transfer analogy, the film cooling effectiveness was measured at various overall mass flow ratios and at various streamwise locations for each coolant type. The division of coolant flow rate from the two rows of holes was found to be more unequal for CO2 than for air, an effect which is predicted from a simple analysis of the coolant/free stream interaction and the hole discharge coefficient. This has practical implications for actual turbine operation since earlier cut-off of the coolant from the front row of holes, due to density differences, could have disastrous effects on the blade. This effect also further complicates any attempt to identify overall trends of coolant density on performance. It is not possible to conclude that air or CO2 coolant has a higher film cooling effectiveness, although, in general, air appears better close to the first row of holes, and CO2 better at some distance downstream of both rows. Based on the measurements, the effects of mass flow ratio, momentum flux ratio, relative hole placement in each row, and spanwise versus streamwise injection are discussed in the paper.
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10

Sharma, Deepakkumar M., and Kamal Poddar. "Determination of Quasi-Steady Characteristics for an Oscillating Airfoil at Varied Reduced Frequency and Reynolds Number." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59298.

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Wind tunnel experiments were conducted on NACA-0015 airfoil model to investigate the effect of the reduced frequency (κ) & Reynolds Number (Re) on the aerodynamic characteristics and hysteresis behavior associated with the pitching motion of the airfoil. Pressure measurements were conducted on the mid span of the airfoil for quantitative results. The hysteresis behavior was observed in aerodynamic characteristics as strong function of reduced frequency in form of a loop which gets enlarged with the increase in the value of reduced frequency. The present investigation of oscillating sinusoidal motion of airfoil, α = 10° + 15° sin(ωt) showed that, under the operating conditions studied, the airfoil was allowed to execute oscillating motion from almost steady (quasi-steady) conditions to unsteadiness with the incremental increase in the reduce frequency. Static conditions show distinct characteristics as compared to dynamic mode. But at extremely low reduced frequency of oscillation even in the dynamic mode the quasi-steady conditions do prevail. This results in a value of reduced frequency upto which the quasi-steady characteristics are preserved. Normal force defect is derived from the surface pressure distribution and the value of reduced frequency within 5% of normal force defect is obtained for varied range of Re to determine and validate the quasi-steady conditions. Re effect is dominant at very low reduced frequency. Also as reduced frequency increases causes decrease in the Re effect and increase in the normal force defect upto certain limiting value. Further increase in the reduced frequency reduces the normal force defect. Effect of Leading edge contamination is also depicted to cause incremental shift in the static stall angle.
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You might also be interested in the extended bibliographies on the topic 'Leading edge contamination' for particular source types:
Journal articles
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