Academic literature on the topic 'Therapy aerodynamic efficiency'
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Journal articles on the topic "Therapy aerodynamic efficiency"
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Machancheri, Fousiya, Mubeena K, and Hemaraja Nayaka. "Voice Quality Measurement as an Indicator of Efficiency of Treatment in Laryngopharyngeal Reflux Disease." Bengal Journal of Otolaryngology and Head Neck Surgery 29, no. 2 (September 27, 2021): 169–75. http://dx.doi.org/10.47210/bjohns.2021.v29i2.466.
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Introduction Laryngopharyngeal reflux disease can alter the structural and functional integrity of the vocal fold. Objectives of the study was to determine the effect of Laryngopharyngeal Reflux Disease (LPRD) on selected Acoustic, Aerodynamic and perceptual parameters of voice and to establish its effectiveness in therapeutic outcome. Materials and Methods The number of patients enrolled for this prospective observational study was 65, all with Reflux symptom index (RSI) more than 13. Quality of life was evaluated using voice handicap index (VHI). Perceptual evaluation of voice done by Grade Roughness Breathiness Asthenia Strain score (GRBAS) followed by acoustic and aerodynamic analysis. Patients were started on a once daily proton pump inhibitor therapy for 3 months along with vocal hygiene measures and RSI, VHI and voice analysis repeated after the treatment. Results There was significant improvement in the RSI score after treatment. Percent jitter and shimmer showed significant improvement in males post treatment (p value:<0.05). Harmonic to noise ratio improved 3 months post treatment in both sexes. Improvement noted in Maximum phonation time and GRBAS score except asthenia and strain post treatment. Conclusion Measurement of voice quality can be used as an effective tool to monitor the efficiency of treatment of LPRD.
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Rodrigues, Susana, Ana da Costa, Noelia Flórez-Fernández, María Torres, Maria Faleiro, Francesca Buttini, and Ana Grenha. "Inhalable Spray-Dried Chondroitin Sulphate Microparticles: Effect of Different Solvents on Particle Properties and Drug Activity." Polymers 12, no. 2 (February 12, 2020): 425. http://dx.doi.org/10.3390/polym12020425.
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Spray-drying stands as one of the most used techniques to produce inhalable microparticles, but several parameters from both the process and the used materials affect the properties of the resulting microparticles. In this work, we describe the production of drug-loaded chondroitin sulphate microparticles by spray-drying, testing the effect of using different solvents during the process. Full characterisation of the polymer and of the aerodynamic properties of the obtained microparticles are provided envisaging an application in inhalable tuberculosis therapy. The spray-dried microparticles successfully associated two first-line antitubercular drugs (isoniazid and rifabutin) with satisfactory production yield (up to 85%) and drug association efficiency (60%–95%). Ethanol and HCl were tested as co-solvents to aid the solubilisation of rifabutin and microparticles produced with the former generally revealed the best features, presenting a better ability to sustainably release rifabutin. Moreover, these presented aerodynamic properties compatible with deep lung deposition, with an aerodynamic diameter around 4 μm and fine particle fraction of approximately 44%. Finally, it was further demonstrated that the antitubercular activity of the drugs remained unchanged after encapsulation independently of the used solvent.
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Gaber, Nazar Noureen, Yusrida Darwis, Kok-Khiang Peh, and Yvonne Tze-Fung Tan. "Characterization of Polymeric Micelles for Pulmonary Delivery of Beclomethasone Dipropionate." Journal of Nanoscience and Nanotechnology 6, no. 9 (September 1, 2006): 3095–101. http://dx.doi.org/10.1166/jnn.2006.426.
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The potential of using poly-(ethylene oxide)-block-distearoyl phosphatidyl-ethanolamine (mPEG-DSPE) polymer to prepare BDP-loaded micelles with high entrapment efficiency and mass median aerodynamic diameter of less than 5 μm demonstrating sustained release properties was evaluated. The result showed that lyophilized BDP-loaded polymeric micelles with entrapment efficiency of more than 96% could be achieved. Entrapment efficiency was affected by both the drug to polymer molar ratio and the amount of drug used. Investigation using FTIR and DSC confirmed that there was no chemical or physical interaction and the drug was molecularly dispersed within the micelles. TEM images showed that the drug-loaded polymeric micelles were spherical in shape with multivesicular morphology. Further analysis by photon correlation spectroscopy indicated that the particle size of the BDP-loaded micelles was about 22 nm in size. In vitro drug release showed a promising sustained release profile over six days following the Higuchi model. The mass median aerodynamic diameter and fine particle fraction were suitable for pulmonary delivery. Moreover, the small amount of deposited drug in the induction port (throat deposition) suggested possible reduction in incidence of oropharyngeal candidiasis, a side effect normally associated with inhaled corticosteroids therapy. The high encapsulation efficiency, comparable inhalation properties, sustained release behavior together with biocompatibility nature of the polymer support the potential of BDP-loaded polymeric micelles as a versatile delivery system to be used in the treatment of asthma and chronic obstructive pulmonary disease.
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Şen, Ayşegül Zencir, and Bülent Toğram. "The Normative Study of Acoustic and Aerodynamic Characteristics of Voice among Healthy Adult Turkish Speaker Population." BioMed Research International 2021 (December 15, 2021): 1–16. http://dx.doi.org/10.1155/2021/9217236.
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Phonatory Aerodynamic System (PAS Model 6600) is an evaluation instrument that assesses the effectiveness of surgical interventions, treatments, and therapy for voice disorders. It can be used for the assessment of voice disorders by supporting other perceptual and instrumental methods. It is important to establish normative data, because the use of appropriate norms is necessary for diagnostic and descriptive accuracy. Therefore, this study is aimed primarily at establishing adult normative databases for phonatory aerodynamic measures obtained with the KayPENTAX PAS Model 6600 among healthy adult Turkish speakers and then examining the effect of age, gender, and age-gender interaction variables on these measures. The contribution of the study is considered so important since it will generate normative data for all measurements—except the mean pitch—by the five protocols of PAS for the first time. Two hundred and six healthy Turkish speakers with normal voice (106 women and 100 men) were included in the study and stratified into three age groups. Forty-five phonatory aerodynamic measures across five PAS protocols (vital capacity, maximum sustained phonation, comfortable sustained phonation, variation in sound pressure level, and voicing efficiency) were collected. Age, gender, and age-gender interaction variables were analyzed for 45 PAS parameters. Significant gender and age effect was found for 30 and 19 variables, respectively. Gender-age interaction together was observed for only 6 parameters. Significant differences were not found for the remaining 10 parameters. Significant age and gender effects were observed for 35 phonatory and aerodynamic measures which are essential part of the objective clinical assessment of voice. Consequently, normative data used as reference in voice assessment should be generated according to age and gender differences.
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de Vasconcelos, Talita Felipe, Bernard Sapoval, José S. Andrade, James B. Grotberg, Yingying Hu, and Marcel Filoche. "Particle capture into the lung made simple?" Journal of Applied Physiology 110, no. 6 (June 2011): 1664–73. http://dx.doi.org/10.1152/japplphysiol.00866.2010.
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Understanding the impact distribution of particles entering the human respiratory system is of primary importance as it concerns not only atmospheric pollutants or dusts of various kinds but also the efficiency of aerosol therapy and drug delivery. To model this process, current approaches consist of increasingly complex computations of the aerodynamics and particle capture phenomena, performed in geometries trying to mimic lungs in a more and more realistic manner for as many airway generations as possible. Their capture results from the complex interplay between the details of the aerodynamic streamlines and the particle drag mechanics in the resulting flow. In contrast, the present work proposes a major simplification valid for most airway generations at quiet breathing. Within this context, focusing on particle escape rather than capture reveals a simpler structure in the entire process. When gravity can be neglected, we show by computing the escape rates in various model geometries that, although still complicated, the escape process can be depicted as a multiplicative escape cascade in which each elementary step is associated with a single bifurcation. As a net result, understanding of the particle capture may not require computing particle deposition in the entire lung structure but can be abbreviated in some regions using our simpler approach of successive computations in single realistic bifurcations. Introducing gravity back into our model, we show that this multiplicative model can still be successfully applied on up to nine generations, depending on particle type and breathing conditions.
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Patel, Priya, Mihir Raval, Aneka Manvar, Vishal Airao, Vaibhav Bhatt, and Pranav Shah. "Lung cancer targeting efficiency of Silibinin loaded Poly Caprolactone /Pluronic F68 Inhalable nanoparticles: In vitro and In vivo study." PLOS ONE 17, no. 5 (May 13, 2022): e0267257. http://dx.doi.org/10.1371/journal.pone.0267257.
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Silibinin (SB) is shown to have an anticancer properties. However, its clinical therapeutic effects have been restricted due to its low water solubility and poor absorption after oral administration. The aim of this study was to develop SB-loaded PCL/Pluronic F68 nanoparticles for pulmonary delivery in the treatment of lung cancer. A modified solvent displacement process was used to make nanoparticles, which were then lyophilized to make inhalation powder, Nanoparticles were characterized with DSC, FTIR,SEM and In vitro release study. Further, a validated HPLC method was developed to investigate the Biodistribution study, pharmacokinetic parameters. Poly Caprolactone PCL / Pluronic F68 NPs showed the sustained release effect up to 48 h with an emitted (Mass median Aerodynamic diameter)MMAD and (Geometric size distribution)GSD were found to be 4.235 ±0.124 and 1.958±1.23 respectively. More specifically, the SB Loaded PCL/Pluronic F 68 NPs demonstrated long circulation and successful lung tumor-targeting potential due to their cancer-targeting capabilities. SB Loaded PCL/Pluronic F68 NPs significantly inhibited tumour growth in lung cancer-induced rats after inhalable administration. In a pharmacokinetics study, PCL/ Pluronic F68 NPs substantially improved SB bioavailability, with a more than 4-fold rise in AUC when compared to IV administration. These findings indicate that SB-loaded PCL/PluronicF68 nanoparticles may be a successful lung cancer therapy delivery system.
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Naseri, Neda, Parvin Zakeri-Milani, Hamed Hamishehkar, Younes Pilehvar-Soltanahmadi, and Hadi Valizadeh. "Development, In Vitro Characterization, Antitumor and Aerosol Performance Evaluation of Respirable Prepared by Self-nanoemulsification Method." Drug Research 67, no. 06 (March 13, 2017): 343–48. http://dx.doi.org/10.1055/s-0043-102404.
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AbstractPoor water solubility and low oral bioavailability limit the clinical application of Erlotinib as an anticancer. For this purpose, we encapsulated erlotinib in the solid lipid nanoparticles (SLN) and designed a spray-dried dry powder inhalable (DPI) formulation. Erlotinib-loaded SLNs were prepared using self-nanoemulsifying and characterized for physicochemical properties. Pulmonary deposition of spray-dried DPI formulation was performed using Next Generation Impactor. The particle size and zeta potential of Erlotinib-loaded SLNs were 300 to 800 nm and −18 to −32 mV, respectively. High drug entrapment efficiency in the narrow range of 80–85% was achieved. Cytotoxicity results indicated that cell growth inhibition of free drug and drug loaded nanoparticles is dose- and time-dependent. Inhalable dry powders prepared from drug-loaded SLNs were found to have a fine particle fraction in the range of 6.92±0.99 –11.24±2.4%, mean mass aerodynamic diameter in the range of 4.52±0.1 to 6.67±0.5 µm. The findings revealed that the proposed inhalable dry powder formulation loaded with erlotinib SLN has potential in lung cancer therapy through pulmonary route.
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Shachar-Berman, Lihi, Saurabh Bhardwaj, Yan Ostrovski, Prashant Das, Pantelis Koullapis, Stavros Kassinos, and Josué Sznitman. "In Silico Optimization of Fiber-Shaped Aerosols in Inhalation Therapy for Augmented Targeting and Deposition across the Respiratory Tract." Pharmaceutics 12, no. 3 (March 5, 2020): 230. http://dx.doi.org/10.3390/pharmaceutics12030230.
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Motivated by a desire to uncover new opportunities for designing the size and shape of fiber-shaped aerosols towards improved pulmonary drug delivery deposition outcomes, we explore the transport and deposition characteristics of fibers under physiologically inspired inhalation conditions in silico, mimicking a dry powder inhaler (DPI) maneuver in adult lung models. Here, using computational fluid dynamics (CFD) simulations, we resolve the transient translational and rotational motion of inhaled micron-sized ellipsoid particles under the influence of aerodynamic (i.e., drag, lift) and gravitational forces in a respiratory tract model spanning the first seven bifurcating generations (i.e., from the mouth to upper airways), coupled to a more distal airway model representing nine generations of the mid-bronchial tree. Aerosol deposition efficiencies are quantified as a function of the equivalent diameter (dp) and geometrical aspect ratio (AR), and these are compared to outcomes with traditional spherical particles of equivalent mass. Our results help elucidate how deposition patterns are intimately coupled to dp and AR, whereby high AR fibers in the narrow range of dp = 6–7 µm yield the highest deposition efficiency for targeting the upper- and mid-bronchi, whereas fibers in the range of dp= 4–6 µm are anticipated to cross through the conducting regions and reach the deeper lung regions. Our efforts underscore previously uncovered opportunities to design the shape and size of fiber-like aerosols towards targeted pulmonary drug delivery with increased deposition efficiencies, in particular by leveraging their large payloads for deep lung deposition.
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Adorni, Greta, Gerrit Seifert, Francesca Buttini, Gaia Colombo, Luciano A. Stecanella, Irene Krämer, and Alessandra Rossi. "Aerosolization Performance of Jet Nebulizers and Biopharmaceutical Aspects." Pharmaceutics 11, no. 8 (August 11, 2019): 406. http://dx.doi.org/10.3390/pharmaceutics11080406.
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In this work, 13 jet nebulizers, some of which in different configurations, were investigated in order to identify the biopharmaceutical constraints related to the quality attributes of the medicinal products, which affect their safety, efficiency, compliance, and effectiveness. The aerosolization parameters, including the aerosol output, aerosol output rate, mass median aerodynamic diameter, and fine particle fraction, were determined according to the European Standard EN 13544-1, using sodium fluoride as a reference formulation. A comparison between the aerosol output nebulization time and the fine particle fraction displayed a correlation between the aerosol quality and the nebulization rate. Indeed, the quality of the nebulization significantly increased when the rate of aerosol emission was reduced. Moreover, the performance of the nebulizers was analyzed in terms of respirable delivered dose and respirable dose delivery rate, which characterize nebulization as the rate and amount of respirable product that could be deposited into the lungs. Depending on which of these two latter parameters was used, the nebulizers showed different performances. The differences, in terms of the rate and amount of delivered aerosol, could provide relevant information for the appropriate choice of nebulizer as a function of drug product, therapy, and patient characteristics.
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Bagre, Archana, Narendra Kumar Lariya, and Mohan Lal Kori. "Therapeutic Management of Pulmonary Tuberculosis by Mannosylated Chitosan Ascorbate Microspheres: Preparation and Characterization." Journal of Drug Delivery and Therapeutics 9, no. 3 (May 15, 2019): 13–25. http://dx.doi.org/10.22270/jddt.v9i3.2805.
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Objective: In this study, biodegradable Chitosan Ascorbate Microsphere (CAMs) and mannosylated chitosan ascorbate microsphere (m-CAMs) prepared for targeting towards alveolar macrophages to treatment of pulmonary tuberculosis.
Significance: Ascorbic acid is an antioxidant and reported killing effect on mycobacterium by induces fenton reaction. This study enlightens the possible benefits of adding antioxidant properties of ascorbic acid with chitosan microsphere to an anti-tuberculosis regimen and mannosylation of microsphere significantly induce the targetability of antitubercular drug to alveolar macrophages.
Methods: CAMs prepared by firstly salification of chitosan by ascorbic acid then ionic gelation with STPP and m-CAMs prepared by incubation method and purified for further studies. The physicochemical, in vitro and in vivo characterizations of both formulations were carried out.
Results: The size of microspheres (both CAMs and m-CAMs) were found to be in range of 3.40-4.81µm. Evident changes were observed in crystallinity and structure of both carrier systems and depicted by Fourier transform infrared (FTIR), Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies. In vitro lung deposition study of microspheres showed favourable aerodynamic properties for deep lung delivery (MMAD 2.0- 3.8 μm) and, thus, show potential for an application as inhalable tuberculosis therapy. The drug release showed the biphasic pattern of release, i.e., initial burst (30-45% up to 8 h) followed by a slower sustained release pattern (more than 80% up to 72 h) in both simulated lung fluids. Optimized formulations exhibited lower cytotoxicity and bio distribution studies demonstrated the efficiency of m-CAMs for spatial delivery of INH to alveolar tissues. CAMs and m-CAMs evidenced minor cytotoxicity on lung epithelial cells (A549 cell lines).
Conclusion: m-CAMs thus has a promising potential to be explore as an effective carrier system for delivery of antitubercular drugs regimen.
Key words: Targetability, alveolar macrophage, lung cancer A549 cells
Dissertations / Theses on the topic "Therapy aerodynamic efficiency"
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Бондар, Валерія Андріївна. "Аеродинаміка і теплообмін труб краплеподібної форми." Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/23241.
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Об’єкт дослідження – процеси аеродинаміки та теплообміну труб
краплеподібної форми при поперечному обтіканні потоком повітря.
Предмет дослідження – вплив режимних параметрів на аеродинамічний
опір і теплообмін труб краплеподібної форми.
Мета роботи – отримання узагальнюючих співвідношень для
розрахунку теплообміну та аеродинамічного опору труб краплеподібної
форми.
Метод дослідження – експериментальне дослідження та CFD-
моделювання.
В даній роботі були проведені експериментальні дослідження та CFD-
моделювання процесів аеродинаміки та інтенсивності конвективного
теплообміну при поперечному обтіканні краплеподібної форми труб, вплив
розташування труб відносно напрямку їх обтікання на інтенсивність
теплообміну та порівняння отриманих результатів з трубами інших форм
поперечного перетину. Була проведена оцінка теплоаеродинамічної
ефективності труб краплеподібної форми. Досліди проведені в діапазоні змін
чисел Рейнольдса ReD = (4..25)·103.
Отримані результати можуть бути використані спеціалістами з
розрахунку теплообмінного обладнання на основі труб краплеподібного
профілю.The object of research - processes of aerodynamics and heat transfer of pipes of a droplet shape with a transverse flow of air. The subject of research - the influence of regime parameters on aerodynamic resistance and heat exchange of tubular droplet forms. The purpose of work – obtaining generalizing relations for calculation of heat transfer and aerodynamic resistance of droplet-shaped tubes. The method of research – experimental research and CFD-modeling. In this paper, experimental studies and CFD-simulation of aerodynamics and convective heat transfer intensity at transverse flow around the drop-shaped tubes, the effect of the arrangement of the pipes in relation to the direction of their flow on the heat transfer intensity and comparison of the results with the pipes of other forms of the cross-section were carried out. An estimation of heat aerodynamic efficiency of droplet-shaped pipes was performed. Experiments are carried out in the range of changes in Reynolds numbers ReD = (4..25)·103. The obtained results can be used by specialists in the calculation of heat- exchange equipment on the basis of pipes of a brittle profile.
Conference papers on the topic "Therapy aerodynamic efficiency"
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Shen, Sheng Chih, and Yu-Jen Wang. "A Novel Handhold High Power MEMS Atomizer Using Micro Cymbal Shape Nozzle Plate for Inhalation Therapy." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86093.
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Inhalation therapy is being applied in the home care field to a gradually increasing degree, and therefore two issues of great importance are the convenience and portability of medical devices. Hence, this paper presents a novel highpower MEMS atomizer device that includes a ring-type piezoelectric actuator and a cymbal-shaped micro nozzle plate (CSNP). The latter can focus energy on the center of the nozzle plate and induce a large force, which provides the MEMS atomizer with the high power necessary to spray medical solutions of high viscosity and increase the atomization rate. The high-power MEMS atomizer can reduce liquids to droplets of an ultra-fine size distribution (Mass Median Aerodynamic Diameter, MMAD), increasing the nebulizing rate and enabling the spraying of high-viscosity fluids (cP>3.5). In this research, the ultra-fine droplets were of a MMAD of less than 4.07 μm at 127.89kHz and the atomization rate was 0.5ml/min. The drive voltage of this high-power MEMS atomizer device was only 3V, and the power consumption only one-tenth that of conventional ultrasonic atomizers at 1.2W. The simulation and experiments carried out in this study proved that the droplets are much smaller than those produced by current conventional devices and the device is of greater efficiency; therefore, the high-power MEMS atomizer is suitable for use in the development of a convenient and portable inhalation therapy device.
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Saha, Ranjan, Jens Fridh, and Mats Annerfeldt. "Aerodynamic Implications of Reduced Vane Count." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42409.
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Given the shortage of fossil fuels and the growing greenhouse effect, one strive in modern gas turbines is to make maximum usage of the burnt fuel. By reducing the number of vanes or blades and thereby increasing the loading per vane (or blade) it is possible to spend less cooling air, which will have a positive impact on the combined cycle efficiency. It also reduces the number of components and usage of metal and thereby also the cost of the engine. These savings should be achieved without any efficiency deficit in aerodynamic efficiency. Based on the fact, aerodynamic investigations were performed to see the aerodynamic implications of reduced vane number in a transonic annular sector cascade. The number of new nozzle guide vane was reduced with 24% compared to a previous design with higher vane count. The investigated vanes were two typical high pressure gas turbine vanes. Results regarding the loading indicated an expected increase with the reduced vane case. The minimum static pressure at the suction side is lower and at an earlier location for the reduced vane case and therefore, an extension of the trailing edge deceleration zone is observed for the reduced vane case. Results regarding losses indicate that even though the losses produced per vane significantly increases for the reduced vane case, a comparison of mass averaged losses between the reduced vane case and previous vane case show similar spanwise loss distributions. Assessing results leads to a conclusion that the reduction of the number of vanes in the first stage seems to be a useful method to save cooling flow as well as material costs without any significant deficit in overall efficiency.
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Brehm, Sebastian, Felix Kern, and Reinhard Niehuis. "CFD Study on the Influence of Geometric Parameters on the Aerodynamics Within an Ejector Injection System for Compressor Stabilization." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75466.
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Injection of high-momentum air into the tip-gap region of rotor stages is a measure of active aerodynamic stabilization of turbo compression systems. The Institute of Jet Propulsion at the University of the German Federal Armed Forces Munich advanced the concept of conventional tip air injection by deliberately deploying the ejector effect in order to increase the mass flow rate of the air injected. A novel Ejector Injection System (EIS) has been developed for the Larzac 04 jet engine and its intended ejector performance was proven in experimental pre-investigations. In addition to that, the corresponding CFD setup has been validated and an approach for highly efficient CFD simulations of the EIS ejector aerodynamics (node number reduction > 90%) was developed, verified, and validated. Thus, optimization of the ejector geometry in order to enhance the ejector aerodynamics and subsequently the stabilization performance of the EIS comes into focus now. Within this paper, a parametric CFD study is conducted to determine the influence of three main geometry parameters of the EIS ejector design on the ejector’s performance. The parameters, namely the injection nozzle spacing, the mixing duct length, and the ejector nozzle height, are introduced in the context of the overall EIS design and functionality. For efficiency purposes, a script-based procedure which deploys ANSYS ICEM CFD and ANSYS CFX has been developed in order to conduct the CFD parameter study covering 205 simulations fully automated. Each ejector geometry is thereby simulated with five different primary air mass flow rates supplied to the EIS covering a range from low-speed to transonic operation. It is revealed that all three geometry parameters investigated show partially significant impact on the ejector performance in terms of the entrainment ratio μ. In order to get a detailed insight into the inner EIS aerodynamics, also primary air Mach and Reynolds numbers, the state of mixing between primary and secondary air, and velocity profiles in the LPC’s tip region are subjects of investigation. Based on these findings and the general aerodynamic coherences discovered, recommendations for optimizing the current EIS ejector design are presented.
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McLean, Christopher, Cengiz Camci, and Boris Glezer. "Mainstream Aerodynamic Effects due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part I — Aerodynamic Measurements in the Stationary Frame." In ASME Turbo Expo 2001: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-gt-0119.
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The relative aerodynamic and performance effects associated with rotor – NGV gap coolant injections were investigated in the Axial Flow Turbine Research Facility (AFTRF) of The Pennsylvania State University. This study quantifies the effects of the coolant injection on the aerodynamic performance of the turbine for radial cooling, impingement cooling in the wheelspace cavity and root injection. Overall, it was found that even a small quantity (1%) of cooling air can have significant effects on the performance character and exit conditions of the high pressure stage. Parameters such as the total-to-total efficiency, total pressure loss coefficient, and three-dimensional velocity field show local changes in excess of 5%, 2%, and 15% respectively. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions.
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Keogh, R. C., G. R. Guenette, C. M. Spadaccini, T. P. Sommer, and S. Florjancic. "Aerodynamic Performance Measurements of a Film-Cooled Turbine Stage: Experimental Results." In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30344.
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Modern high performance gas turbine engines utilize film cooling to reduce the heat load on high-pressure turbine stage components, thereby increasing the maximum turbine inlet temperature at which the cycle can operate. However, increased turbine inlet temperature comes at the expense of a reduction in turbine efficiency. The objective of this research is to measure the aerodynamic performance of a film cooled turbine stage and to quantify the loss caused by film cooling. An un-cooled turbine stage was first fabricated with solid blading and tested using a newly developed short duration measurement technique. The stage was then modified to incorporate vane, blade and rotor casing film cooling. The film-cooled stage was then tested over a range of coolant-to-mainstream mass flow and temperature ratios for the same range of operating conditions (pressure ratios and corrected speeds) as the un-cooled turbine. This paper presents the experimental results for these two series of tests.
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Ellbrant, Lars, Lars-Erik Eriksson, and Hans Mårtensson. "Design of Compressor Blades Considering Efficiency and Stability Using CFD Based Optimization." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69272.
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To design a highly loaded axial transonic compressor several objectives need to be considered simultaneously. From an aerodynamic perspective, one of the major requirements is high efficiency at a specific operating condition where the fuel consumption is of main interest. Furthermore, the compressor needs to have a sufficient stall-margin along the entire flight envelope to ensure a stable operating range. This work is focused on creating an efficient design method which produces a trade-off between high stall margin and high efficiency. The design method is based on an automatic multiobjective optimization process divided into two steps. In the first step, 2D blade profiles are optimized where both efficiency and stall margin are considered. Once the optimization is finished the selected profiles are stacked together to be further optimized in 3D. When going to the second step, i.e. a 3D optimization, one can focus on a smaller set of design variables thereby reducing the time to get what is considered the optimal solution. The results show that it is possible to rate designs with potential of having high stall margin and high efficiency both in the 2D and 3D optimization. The main contribution in this work is the design method, which offers an efficient way of designing robust blades where the designer can decide the best trade off between stall margin at part speed and efficiency at the design point.
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Janke, E., F. Haselbach, C. Whitney, V. Kanjirakkad, R. Thomas, and H. Hodson. "Passive Shroud Cooling Concepts for HP Turbines: CFD Based Design Approach." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91194.
Full textAbstract:
One option to improve the cycle efficiency of current state-of-the-art aero engines is to increase the turbine inlet temperature. Since this temperature is above the melting temperature for the alloys utilised in the turbine component already today, efficient cooling methods must be developed that consider both aerodynamic and aerothermal aspects of cooling. Here, the goal is to extract as little as possible secondary air from the main hot gas cycle for cooling and to use this coolant then aerodynamically and aerothermally as efficient as possible. The paper to be presented documents a CFD based design approach that lead to a new passive shroud cooling concept and the definition of its operational parameters. By using a simple one dimensional method [10] for predicting the aerodynamic losses resulting from such a cooling configuration in connection with 3d Navier-Stokes solvers (RANS) for predicting film cooling effectiveness contours on the rotor shroud surfaces, the new cooling configuration was developed. The concept was then tested and confirmed experimentally as documented in more detail in Part 2 of this paper. It is noted that only 70% of the coolant mass flow required for the current configuration was used for the new concept whereas the aerodynamic efficiency measured remained nearly constant. Improving upon existing passive shroud cooling systems where the coolant is injected directly into the labyrinth of the shroud, the new approach comprises cooling holes that inject the coolant upstream of the labyrinth and through the stator platform into the main passage flow. Here, it is important that the bulk of the coolant is placed below the dividing streamlines between main passage flow and labyrinth flow. Thereby, it can be achieved that the major part of the coolant indeed reaches the thermally loaded target surfaces on the shroud bottom at various axial gaps due to different operating points of the turbine. Besides the improved film-cooling effectiveness measured, the second important aspect of the new concept is the achievement of as small as possible additional aerodynamic losses due to coolant ejection into a high speed flow region. It will be shown that both goals can be achieved by the new concept. Furthermore, CFD results on film-cooling performance and aerodynamic losses will be shown and compared with experimental data.
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Atiqullah, Mir, Rigoverto Sanchez, and Benjamin Hamler. "Undergraduate Research on Trailer-Truck Aerodynamic Drag." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65218.
Full textAbstract:
The transportation industry is heavily dependent on ‘big rigs’ or semitrailers. Since its introduction during 1920s semitrailers have revolutionized the industry. However their geometrical designs have not evolved much to make them aerodynamically more streamlined, thus more fuel efficient. While over 5.6 million such commercial trailer trucks are registered in the country and with increasing diesel fuel prices, it is more important than ever to study their aerodynamics, redesign for reducing aerodynamic drag and help make these ‘big rigs’ more fuel efficient. Aerodynamic drag is the force that acts on a solid object moving in air due to difference in dynamic pressure developed around that object. Skin friction also causes resistance force which is small compared to pressure induced drag. Higher drag resistance, just like road and tire resistance, causes loss of energy and thereby lowers fuel mileage. Drag resistance is caused by both surface friction as well as air pressure difference around a moving object/vehicle. An ideal remedy is of course to completely redesign the shape and size of these semitrailers to conform to those with known low drag. Another intermediate approach would be to retrofit the existing semitrailers with devices that change the overall shape towards more aerodynamic ones. During the recent past a wide range of such add on devices have been introduced. Current research was directed in two fronts: CAD and Drag simulation as well as experimental drag testing. First a base CAD model and then various modifications were developed using an industry standard CAD package. These models were then imported into Computational Fluid Dynamics (CFD) software. These followed by modeling add-on devices to reduce drag. The simulations were repeated with various combinations of these add-on drag reducers. The areas targeted for drag reduction study included gap between tractor and trailer, lower sides of the trailer between front and rear wheel sets, and rear of the trailer. The results showed varying effectiveness of these add-on devices, individually and in combination. Scale models of the trailer truck were built using wood as well as Rapid Prototyping (RP) directly from CAD using polymer. These models were then tested in the wind tunnel at speeds between 35 and 75 miles per hour. The data and the trends in Cd values compared well with the simulated values. The overall CFD and scale model studies provided a comprehensive knowledge and understanding of the drag in semi-trailers and factors that affect it. Future studies may expand the varieties and locations of these devices as well as complete redesigns of the trailer-trucks.
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Vassiliev, Vladimir, Andrey Granovskiy, and Nikolai Lomakin. "Impact of Turbine Blade Internal Cooling on Aerodynamic Loss." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42696.
Full textAbstract:
Modern gas turbines operate at high temperature, which exceed the endurance limit of material, and therefore the turbines components have to be cooled by the air taken from the compressor. The cooling providing positive impact on lifetime of GT has negative impact on its performance. Firstly because the cooling air bypasses combustor and its capacity is not fully utilized. This effect is usually accounted in thermodynamic calculations of gas turbine. Secondly the injection of cooling air in the turbine disturbs the main flow, and may lead to increased losses. In addition cooling requirements lead to limitation on the blade shape (e.g. limiting the minimal size of trailing edge) and thereby negatively affect the losses. These effects were already discussed in the literature, but further investigations for better understanding of flow physics and design improvement are still useful. There is also additional impact of cooling - impact of heat transfer on near wall boundary layer and coolant properties. This effect was not sufficiently discussed in the open literature, where quite often the walls are considered as adiabatic. The paper consists of two main parts. In the first part the results of experimental investigations of several linear cascades with and without trailing edge injection are presented and discussed. In the second part the results of detailed numerical investigations of one of these cascades are presented. One set of calculations were done at the test rig conditions for comparison with measured data. These calculations were used for validation of CFD model. The next sets of calculations were done for engine typical conditions, including the simulation of blade material temperature. The calculations were performed for adiabatic wall and for surface with heat transfer, including the impact of heat transfer on coolant injection. This analysis provides split of losses caused by different factors, and offers the opportunities for efficiency and lifetime improvements of real engine designs/upgrades.
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Dahlquist, Adrian, and Magnus Genrup. "Aerodynamic Turbine Design for an Oxy-Fuel Combined Cycle." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56439.
Full textAbstract:
The oxy-fuel combined cycle (OCC) is one of several carbon capture and sequestration (CCS) technologies being developed to reduce CO2 emissions from thermal power plants. The OCC consists of a semi-closed topping Bryton cycle, and a traditional bottoming Rankine cycle. The topping cycle operates with a working medium mixture of mainly CO2 and H2O. This CO2-rich working fluid has significantly different gas properties compared to a conventional open gas turbine cycle, which thereby affects the aerodynamic turbine design for the gas turbine units. The aerodynamic turbine design for oxy-fuel gas turbines is an unexplored research field. The topic of this study was therefore to investigate the aerodynamic turbine design of turbines operating with a CO2-rich working fluid. The investigation was performed through a typical turbine aero-design loop, which covered the 1D mid-span, 2D through-flow, 3D blade profiling design and the steady-state 3D analysis. The design was performed through the use of conventional design methods and criteria in order to investigate if any significant departures from conventional turbine design methods were required. The survey revealed some minor deviations in design considerations, yet it showed that the design is feasible with today’s state-of-the-art technology by using conventional design practice and methods. The performance of the oxy-fuel combined cycle was revised based on the performance figures from the components design. The expected total performance figures for the oxy-fuel combined cycle were calculated to be a net electrical power of 119.9 MW and a net thermal efficiency of 48.2%. These figures include the parasitic consumption for the oxygen production required for the combustion and the CO2 compression of the CO2 bleed stream.