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S. A. Kha - One of the best experts on this subject based on the ideXlab platform.
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Effect of Nozzle Pressure Ratio and Control Jets Location to Control Base Pressure in Suddenly Expanded Flows
Isfahan University of Technology, 2019Co-Authors: K. A. Patha, P. S. Dabee, S. A. KhaAbstract:In this paper, computational fluid dynamic (CFD) analysis and experiments have been carried out to study the effect of Nozzle Pressure ratio, i.e. the ratio of inlet Pressure to atmospheric Pressure, and the pitch circle diameter of the control jets to regulate the base Pressure. The variables considered for the analysis as well as the experiments are the Nozzle Pressure ratio (NPR), the Mach number (M) and the pitch circle diameter (PCD) of the control jets. The area ratio considered for the study is kept constant at 4.84 while the length to diameter (L/D) ratio of an enlarged duct is set constant at 5. The inertia parameter considered for the study is Mach number. The Mach numbers considered for study are 1.5, 2.0, and 2.5. The Nozzle Pressure ratio considered for study are 2, 5 and 8. Three different pitch circle diameters of control jets considered for study are 13.1 mm, 16.2 mm and 19.3 mm. From the numerical simulations and the results of the experimental tests, it is found that the control jets are very beneficial to increase the base Pressure at higher NPR when the jets issuing from the Nozzles are under-expanded. The control jets were able to increase the base Pressure value from 160% to 400% at Nozzle Pressure ratio 8. It is concluded that the parameter D3 is the most effective pitch circle diameter of the control jets to increase the base Pressure
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optimization of area ratio and thrust in suddenly expanded flow at supersonic mach numbers
Case Studies in Thermal Engineering, 2018Co-Authors: K. A. Patha, P. S. Dabee, S. A. KhaAbstract:Abstract In this investigation the flow field has been computed by the numerical approach using Computational Fluid Dynamics (CFD) Analysis to investigate the efficacy of the supersonic Mach numbers due to the flow from supersonic Nozzle exhausted in a larger circular duct and the corresponding thrust force created due assess the flow development in the circular pipe, its measurement and the magnitude. For this study the Nozzles were modeled using academic licensed ANSYS Workbench software. The Nozzles were modeled for the Mach numbers 1.5, 2.0 and 2.5. The flow from the Nozzles was numerically simulated for Nozzle Pressure ratios (NPRs) in the range from 2 to 8, and the area ratios of the study were 2, 4, 6, 8 and 10. The simulation results were compared for geometrical and the kinematical parameters. The results indicate that the Pressure in the base corner of enlarged duct is influenced by the level of expansion (i.e. Nozzle Pressure ratio), inertia level (i.e. Mach number) at the Nozzle exit and the relief available (i.e. area ratio) to the shear layer. If the maximum thrust is the aim then the optimum area ratios should be considered. Lower area ratio is not suitable for higher NPR and higher area ratio is not suitable for lower NPR. The higher area ratio provides more space to expand compressed air. Also, the lower area ratio will offer minimum base drag. The base drag is strongly influenced by the area ratio up to certain limit. If the area ratio is again increases then there is no effect of increase in the area ratio on the base drag and Thrust. As the Mach number increases for the same Nozzle Pressure ratio and the area ratio, the net thrust force also increases. From the obtained results the optimum area ratio can be selected to maximize thrust for a given Nozzle Pressure ratio and Mach number.
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cfd analysis of effect of area ratio on suddenly expanded flows
International Conference for Convergence for Technology, 2017Co-Authors: K. A. Patha, S. A. Kha, P. S. DabeeAbstract:This paper presents the Computational Fluid Dynamic (CFD) analysis to study the effect of area ratio i.e. the ratio of enlarged duct area to Nozzle exit area on velocity distribution along axis by varying the Nozzle Pressure ratios. The convergent-divergent Nozzle and suddenly expanded circular duct of larger cross-sectional area are used for analysis. The analysis is done for Mach number 2.0 by varying the area ratios and Nozzle Pressure ratios. The area ratios for the analysis are 1, 2, 4, 6, 8, 10 and 12. The values of Nozzle Pressure ratios considered are 2, 4, 6, 8, 10 and 12. The results are compared with the help of graphs and tables. By observing all the results it can be concluded that the flow field in the enlarged duct is strongly influenced by area ratios and Nozzle Pressure ratios.
Hüseyin Gazi Örtlek - One of the best experts on this subject based on the ideXlab platform.
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Influence of Selected Process Variables on the Mechanical Properties of Core-Spun Vortex Yarns Containing Elastane
Fibres & Textiles in Eastern Europe, 2006Co-Authors: Hüseyin Gazi ÖrtlekAbstract:In this experimental study, we investigated the effects of Nozzle Pressure, delivery speed and elastane content on the mechanical properties of core-spun yarns produced using the Murata vortex spinning system. Our findings show that the Nozzle Pressure, delivery speed, elastane content as expressed by the linear density of elastane yarn and the interactions of these factors are all significant factors affecting the mechanical properties of core-spun vortex yarns. Core-spun vortex yarns containing elastane show higher elongation at break and lower tenacity values than vortex yarns which contain no elastane. Increases in the Nozzle Pressure and decreases in the delivery speed resulted in significantly deteriorated mechanical properties of core-spun vortex yarns containing elastane.
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effect of some variables on properties of 100 cotton vortex spun yarn
Textile Research Journal, 2005Co-Authors: Hüseyin Gazi Örtlek, Sukriye UlkuAbstract:This paper examines the influence of various parameters such as delivery speed, Nozzle Pressures, and yarn count on the properties of vortex yarns produced using a Murata vortex spinning system. The results indicated that the delivery speed, Nozzle Pressure, and yarn count are all significant parameters for yarn evenness, imperfections, hairiness and tensile properties. Our findings show that increasing the delivery speed increases the hairiness and decreases the number of neps, and the tensile properties of vortex yarns. When the Nozzle Pressure increases, yarn unevenness, the number of thick places, the neps values, and the tensile properties of vortex yarns increases but the hairiness values of vortex yarns decreases. In general, the physical, the hairiness, and the tensile properties of coarser vortex yarns are better than finer yarns.
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Effect of Some Variables on Properties of 100% Cotton Vortex Spun Yarn:
Textile Research Journal, 2005Co-Authors: Hüseyin Gazi Örtlek, Sukriye UlkuAbstract:This paper examines the influence of various parameters such as delivery speed, Nozzle Pressures, and yarn count on the properties of vortex yarns produced using a Murata vortex spinning system. The results indicated that the delivery speed, Nozzle Pressure, and yarn count are all significant parameters for yarn evenness, imperfections, hairiness and tensile properties. Our findings show that increasing the delivery speed increases the hairiness and decreases the number of neps, and the tensile properties of vortex yarns. When the Nozzle Pressure increases, yarn unevenness, the number of thick places, the neps values, and the tensile properties of vortex yarns increases but the hairiness values of vortex yarns decreases. In general, the physical, the hairiness, and the tensile properties of coarser vortex yarns are better than finer yarns.
S A Khan - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the effects of Nozzle exit mach number and Nozzle Pressure ratio on axisymmetric flow through suddenly expanded Nozzles
2019Co-Authors: S A Khan, A K M Mohiuddin, Ahmad C Saleel, Fharukh Ahmed G MAbstract:Computational Fluid Dynamics simulations were carried out using ANSYS FLUENT for suddenly expanded flow through the convergent-divergent Nozzle and a suddenly expanded duct. The Length-to-Diameter ratio of 10 for the duct was used in the analysis. Also, an Area Ratio between CD Nozzle exit area and Duct Area was used to be 1.6. The effects of Nozzle Exit Mach number and the Nozzle Pressure Ratios were evaluated by conducting the simulations for Nozzle Exit Mach numbers: 1.87, 2.25 and 2.58. For each Mach number then, Nozzle Pressure Ratios of 3, 5, 7, 9, and 11 were set respectively. Making a total of 15 cases. All the cases were simulated using the k-ω turbulence model. Simulated results agree with the experimental data. From the analysis, it is clear that the Nozzle Exit Mach number and Nozzle Pressure Ratio have a direct effect on the expanded flow exiting the Nozzle.
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Investigation of efficacy of low length-to-diameter ratio and Nozzle Pressure ratio on base Pressure in an abruptly expanded flow
MATEC Web of Conferences, 2018Co-Authors: Fharrukh Ahmed, S A KhanAbstract:This study has been carried out to assess the efficacy of the flow regulations in the form of tiny jets to regulate the Pressure in the base region of an abruptly expanded duct. Four tiny jets of 1mm diameter placed at 90 intervals at 6.5 mm distance from the main jet in the wake region of the base were employed as flow management mechanism. The experiments were conducted at the inertia level of M = 2.5 & 3.0. The jets from the Nozzles were expanded abruptly into a circular duct with four cross-sectional areas of 2.56, 3.24, 4.84 and 6.25. The L/D ratio of the enlarged duct considered was from 10 to 1 and experiments were conducted for Nozzle Pressure Ratio (NPR) from 3 to 11. Since the jets Mach numbers are high and the highest NPR tested was 11 which imply that the flow remains over expanded, even though, with increase in the NPR, the level of over expansion will decrease. It is well known that for over expanded Nozzles an oblique shock will be formed at the Nozzle lip, which in turn will result in the increase of the base Pressure once it passes through the shock wave. From the results it is observed that for the NPRs 3 and 5 there is no appreciable gain in the base Pressure, and hence, control employed as tiny jets are not effective, however, at NPR 7, 9, and 11 there is remarkable change in the base Pressure values. This clearly indicates that NPR plays a significant role to decide on the magnitude of the base Pressure and the control efficacy of the flow regulation mechanism as the tiny jets. It is found that the present method of flow regulation mechanism can be used as effective regulator of the base flows in an abruptly expanded duct. The control does not alter the nature of the flow in the enlarge duct.
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cfd analysis of cd Nozzle and effect of Nozzle Pressure ratio on Pressure and velocity for suddenly expanded flows
International Journal of Mechanical and Production Engineering Research and Development, 2018Co-Authors: S A Khan, Abdul Abid, Maugal Ahmed Ali BaigAbstract:A numerical work was carried out to study the effectiveness of micro-jets to control base Pressure in suddenly expanded two-dimensional planar duct. Two micro-jets of 1 mm orifice diameter located at 90° intervals along a pitch circle distance of 1.5 times the Nozzle exit diameter in the base region were employed as active controls. The calibrated Mach numbers at the entry to suddenly expanded duct was 1.87. The length-to-diameter ratio (L/D) of suddenly expanded duct was 10. Nozzles generating the calibrated Mach numbers were operated with Nozzle Pressure ratio (NPR) 3, 5, 7, 9 and 11. From the present investigation it is evident that for a given Mach number and effect of NPR will result in maximum increase/decrease of Pressure and velocity. The convergent-divergent Nozzle geometry has been modeled and simulated employing turbulence models: K-e standard wall function turbulence model from the code was independently checked with the commercial computational fluid dynamics.
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CFD analysis of effect of flow and geometry parameters on thrust force created by flow from Nozzle
2017 2nd International Conference for Convergence in Technology (I2CT), 2017Co-Authors: Khizar Ahmed Pathan, S A Khan, P. S. DabeerAbstract:This paper presents the Computational Fluid Dynamic (CFD) analysis to study the effect geometry and flow parameters on thrust force created by the flow from convergent-divergent Nozzles to a suddenly expanded circular duct of larger cross-sectional area. The study is focusing on resultant thrust force. The Nozzles are designed for Mach numbers 1.1, 1.4, 1.8 and 2.0. The CFD analysis is done by varying the area ratios and Nozzle Pressure ratios for all Mach numbers. The area ratios considered for the analysis are 1, 2, 4, 6, 8, 10 and 12. The values of Nozzle Pressure ratios considered in the analysis are 2, 4, 6, 8, 10 and 12. The results for different combinations of Mach number, area ratios and Nozzle Pressure ratios are compared with the help of tables. By observing all the results it can be concluded that the resultant thrust force created by flow through Nozzle is strongly influenced by Mach number, area ratio and Nozzle Pressure ratio.
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cfd analysis of effect of mach number area ratio and Nozzle Pressure ratio on velocity for suddenly expanded flows
International Conference for Convergence for Technology, 2017Co-Authors: Khizar Ahmed Pathan, S A Khan, P. S. DabeerAbstract:This paper presents the Computational Fluid Dynamic (CFD) analysis to study the effect of Mach numbers on velocity distribution at different area ratio and Nozzle Pressure ratio in the flow field from convergent-divergent Nozzles to a suddenly expanded circular duct of larger cross-sectional area. The study is focusing on velocity distribution along axial length. The analysis is done for Mach numbers 1.4 and 1.8 by varying the area ratios and Nozzle Pressure ratios. The area ratios for the analysis are 1, 2, 4, 6, 8, 10 and 12. The values of Nozzle Pressure ratios considered for analysis are 2, 4, 6, 8, 10 and 12. The results are plotted with the help of graphs. By observing all the results it can be concluded that the flow field in the enlarged duct is strongly influenced by Mach numbers, area ratios and Nozzle Pressure ratios.
Youngmo Koo - One of the best experts on this subject based on the ideXlab platform.
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Nozzle Pressure Response Characteristics of Variable Rate System for Unmanned Aerial Applications
Journal of Biosystems Engineering, 2019Co-Authors: Youngmo KooAbstract:As interest in the variable rate application (VRA) increases, it is necessary to study the characteristics of the Nozzle Pressure applied for unmanned aerial applications. In this study, therefore, we analyzed the performance of Nozzle Pressure responses to the ground velocity in an unmanned rotorcraft test bed. Then, the responses using air chamber and Kalman filter were compared for reducing the pulsation and time delay. For the VRA system test, an unmanned agricultural rotorcraft with a commercial controller was used as a test bed for the VRA of the aerial pesticide application. The VRA system responses with air chamber and Kalman filter were measured when the system was switched on and off during flight maneuvers. Then, the lag time and pulsation were determined. Pulsation of Nozzle Pressure has been conventionally relieved using an air chamber, but the response of the Nozzle Pressure is delayed by 2.6–3.8 s. This delay could lead to a significant error in the application rate and uniformity in the case of high spraying speeds. Therefore, the air chamber method was excluded from the use in variable control applications. As an alternative, the Pressure response was gently induced by employing the Kalman filter in the control S/W. The optimal covariances of the Kalman filter were found to be R = 100 and Q = 1, and the response time of the Nozzle Pressure was estimated to be less than 0.1 s. To alleviate the time lag and pulsation of Nozzle Pressure, it was necessary to reduce the variation of the pulse width modulation (PWM) voltage relative to the ground velocity. The VRA system with Kalman filter would be implemented in unmanned rotorcraft for aerial application purpose. Consequently, the adaptation of Kalman filter technology enables to improve spray uniformity along the flight trajectory.
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Nozzle Pressure Response Characteristics of Variable Rate System for Unmanned Aerial Applications
Journal of Biosystems Engineering, 2019Co-Authors: Youngmo KooAbstract:Purpose As interest in the variable rate application (VRA) increases, it is necessary to study the characteristics of the Nozzle Pressure applied for unmanned aerial applications. In this study, therefore, we analyzed the performance of Nozzle Pressure responses to the ground velocity in an unmanned rotorcraft test bed. Then, the responses using air chamber and Kalman filter were compared for reducing the pulsation and time delay. Methods For the VRA system test, an unmanned agricultural rotorcraft with a commercial controller was used as a test bed for the VRA of the aerial pesticide application. The VRA system responses with air chamber and Kalman filter were measured when the system was switched on and off during flight maneuvers. Then, the lag time and pulsation were determined. Results Pulsation of Nozzle Pressure has been conventionally relieved using an air chamber, but the response of the Nozzle Pressure is delayed by 2.6–3.8 s. This delay could lead to a significant error in the application rate and uniformity in the case of high spraying speeds. Therefore, the air chamber method was excluded from the use in variable control applications. As an alternative, the Pressure response was gently induced by employing the Kalman filter in the control S/W. The optimal covariances of the Kalman filter were found to be R = 100 and Q = 1, and the response time of the Nozzle Pressure was estimated to be less than 0.1 s. Conclusions To alleviate the time lag and pulsation of Nozzle Pressure, it was necessary to reduce the variation of the pulse width modulation (PWM) voltage relative to the ground velocity. The VRA system with Kalman filter would be implemented in unmanned rotorcraft for aerial application purpose. Consequently, the adaptation of Kalman filter technology enables to improve spray uniformity along the flight trajectory.
Sukriye Ulku - One of the best experts on this subject based on the ideXlab platform.
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effect of some variables on properties of 100 cotton vortex spun yarn
Textile Research Journal, 2005Co-Authors: Hüseyin Gazi Örtlek, Sukriye UlkuAbstract:This paper examines the influence of various parameters such as delivery speed, Nozzle Pressures, and yarn count on the properties of vortex yarns produced using a Murata vortex spinning system. The results indicated that the delivery speed, Nozzle Pressure, and yarn count are all significant parameters for yarn evenness, imperfections, hairiness and tensile properties. Our findings show that increasing the delivery speed increases the hairiness and decreases the number of neps, and the tensile properties of vortex yarns. When the Nozzle Pressure increases, yarn unevenness, the number of thick places, the neps values, and the tensile properties of vortex yarns increases but the hairiness values of vortex yarns decreases. In general, the physical, the hairiness, and the tensile properties of coarser vortex yarns are better than finer yarns.
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Effect of Some Variables on Properties of 100% Cotton Vortex Spun Yarn:
Textile Research Journal, 2005Co-Authors: Hüseyin Gazi Örtlek, Sukriye UlkuAbstract:This paper examines the influence of various parameters such as delivery speed, Nozzle Pressures, and yarn count on the properties of vortex yarns produced using a Murata vortex spinning system. The results indicated that the delivery speed, Nozzle Pressure, and yarn count are all significant parameters for yarn evenness, imperfections, hairiness and tensile properties. Our findings show that increasing the delivery speed increases the hairiness and decreases the number of neps, and the tensile properties of vortex yarns. When the Nozzle Pressure increases, yarn unevenness, the number of thick places, the neps values, and the tensile properties of vortex yarns increases but the hairiness values of vortex yarns decreases. In general, the physical, the hairiness, and the tensile properties of coarser vortex yarns are better than finer yarns.
