The Experts below are selected from a list of 75555 Experts worldwide ranked by ideXlab platform
Zhengyin Ye - One of the best experts on this subject based on the ideXlab platform.
-
flow Control over the blunt trailing edge of wind turbine airfoils using Circulation Control
Energies, 2018Co-Authors: Heyong Xu, Chenliang Qiao, Qingli Dong, Zhengyin YeAbstract:A new partial Circulation Control (PCC) method is implemented on the blunt trailing edge DU97-Flatback airfoil, and compared with the traditional full Circulation Control (FCC) based on numerical analysis. When the Coanda jet is deactivated, PCC has an attractive advantage over FCC, since the design of PCC doesn’t degrade aerodynamic characteristics of the baseline flatback section, in contrast to FCC, which is important in practical use in case of failure of the Circulation Control system. When the Coanda jet is activated, PCC also outperforms FCC in several respects. PCC can produce much higher lift coefficients than FCC over the entire range of angles of attack as well as the entire range of jet momentum coefficients under investigation, but with slightly higher drag coefficients. The flow field of PCC is less complex than that of FCC, indicating less energy dissipation in the main flow and hence less power expenditure for the Coanda jet. The aerodynamic figure of merit (AFM) and Control efficiency for Circulation Control are defined, and results show that PCC has much higher AFM and Control efficiency than FCC. It is demonstrated that PCC outperforms FCC in terms of effectiveness, efficiency and reliability for flow Control in the blunt trailing edge wind turbine application.
-
active Circulation Control on the blunt trailing edge wind turbine airfoil
AIAA Journal, 2017Co-Authors: Heyong Xu, Chenliang Qiao, Huiqiang Yang, Zhengyin YeAbstract:Active Circulation Control on a thick blunt trailing edge wind turbine airfoil is proposed and numerically investigated by solving Reynolds-averaged Navier–Stokes equations along with Spalart–Allma...
Heyong Xu - One of the best experts on this subject based on the ideXlab platform.
-
flow Control over the blunt trailing edge of wind turbine airfoils using Circulation Control
Energies, 2018Co-Authors: Heyong Xu, Chenliang Qiao, Qingli Dong, Zhengyin YeAbstract:A new partial Circulation Control (PCC) method is implemented on the blunt trailing edge DU97-Flatback airfoil, and compared with the traditional full Circulation Control (FCC) based on numerical analysis. When the Coanda jet is deactivated, PCC has an attractive advantage over FCC, since the design of PCC doesn’t degrade aerodynamic characteristics of the baseline flatback section, in contrast to FCC, which is important in practical use in case of failure of the Circulation Control system. When the Coanda jet is activated, PCC also outperforms FCC in several respects. PCC can produce much higher lift coefficients than FCC over the entire range of angles of attack as well as the entire range of jet momentum coefficients under investigation, but with slightly higher drag coefficients. The flow field of PCC is less complex than that of FCC, indicating less energy dissipation in the main flow and hence less power expenditure for the Coanda jet. The aerodynamic figure of merit (AFM) and Control efficiency for Circulation Control are defined, and results show that PCC has much higher AFM and Control efficiency than FCC. It is demonstrated that PCC outperforms FCC in terms of effectiveness, efficiency and reliability for flow Control in the blunt trailing edge wind turbine application.
-
active Circulation Control on the blunt trailing edge wind turbine airfoil
AIAA Journal, 2017Co-Authors: Heyong Xu, Chenliang Qiao, Huiqiang Yang, Zhengyin YeAbstract:Active Circulation Control on a thick blunt trailing edge wind turbine airfoil is proposed and numerically investigated by solving Reynolds-averaged Navier–Stokes equations along with Spalart–Allma...
Dennis Keller - One of the best experts on this subject based on the ideXlab platform.
-
Aerodynamic Analysis of a STOL Propeller Aircraft with Active High-Lift and Control Surface Systems
Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 2020Co-Authors: Dennis Keller, Ralf RudnikAbstract:The aerodynamic properties of a state-of-the-art short take-off and landing aircraft design with Circulation Control and slipstream deflection in landing configuration have been investigated via RANS simulations. The present paper summarizes the findings concerning one engine inoperative conditions (OEI), active Control surface design, and ground effect. It is shown that the unfavorable aircraft’s aerodynamic characteristics under OEI conditions, including a degraded maximum lift coefficient and extraordinarily high yawing moments, can be improved via passive measures, such as nacelle strakes and tail fences. The resulting requirements for lateral Control forces can be fulfilled by the use of Circulation Controlled rudder and ailerons. Simulations of the 3D configuration in ground proximity yield a beneficial effect on the lift coefficient despite contrary indications from 2D computations. Furthermore, the simulations show a significant pitch down tendency due to ground proximity.
-
Investigation and improvement of directional stability and Control of a propeller-driven STOL aircraft
CEAS Aeronautical Journal, 2019Co-Authors: Dennis Keller, Ralf RudnikAbstract:The scope of this paper is to investigate and improve the aerodynamic properties of a propeller driven state-of-the-art active high-lift configuration in lateral motion. 3D RANS simulations of the landing configuration with Circulation Control and slipstream deflection under crosswind, and one engine inoperative (OEI) conditions were performed. The configuration shows directionally unstable behavior at small sideslip angles and high yawing moment production under OEI conditions. Flowfield analyses indicate that both can be attributed to wake-tail interference effects caused by slipstream–vortex interaction. The integration of tail fences at the rear of the fuselage leads to considerable improvements for both conditions.
-
Investigation and Improvement of Directional Stability and Control under Slipstream Effects
2018 AIAA Aerospace Sciences Meeting, 2018Co-Authors: Dennis Keller, Ralf RudnikAbstract:The scope of this paper is to investigate and improve the aerodynamic properties of a propeller driven active high-lift configuration in lateral motion. Therefore, results of 3D RANS simulations of a landing configuration with Circulation Control and slipstream deflection under crosswind and one engine inoperative (OEI) conditions are discussed. The configuration shows directionally unstable behavior at small sideslip angles and high yawing moment production under OEI conditions. Flowfield analysis indicate that both can be attributed to wake-tail interference effects, caused by slipstream-vortex interaction. The integration of tail fences at the rear of the fuselage leads to considerable improvements under both conditions.
-
Numerical Assessment of a High‐Lift Configuration with Circulation Control and flexible Droop Nose
2015Co-Authors: Marco Burnazzi, Dennis KellerAbstract:The use of active flow Control in high-lift systems is a promising solution to improve aircraft low-speed capabilities and reduce noise emissions during landing. To date, however, the system power requirements have been too high in relation to the achieved lift gains, to allow a large use of these technologies in the aeronautical industry. The present work addresses this problem by developing and testing a leading-edge device to increase the efficiency of an internally-blown Coanda-flap configuration. The main objectives are the increase of the stall angle of attack and the reduction of the jet momentum requirements. A 2D sensitivity analysis is performed to explore the effects of varying the airfoil camber and thickness in the first 20% of the airfoil chord. The resulting droop-nose configuration yields a reduction of 32% of the jet momentum required to achieve a target maximum lift coefficient of 5.0, while improving the stall angle by 10°. As the modified leading edge geometry presents different stall mechanisms, the aerodynamic response to variations of jet momentum is also different. In particular, for a jet momentum coefficient above 0.035 the stall angle of attack increases with jet momentum, in contrast to the behavior observed with the baseline leading-edge configuration. Subsequent to the 2D study, the results are tested on a wing-body configuration with a Circulation Controlled plain flap, which is deflected by 65°. Therefore, calculations at an identical blowing coefficient are performed on the clean-nose and droop-nose configurations. The comparison of the 3D results verifies the stall delay observed in 2D. The outboard leading edge stall seen on the clean-nose configuration is successfully suppressed. In contrast, the maximum lift of the droop-nose configuration is limited due to fuselage-wing integration effects. As a result, the increase of the maximum lift coefficient is limited to 3%, whereas the maximum angle of attack is raised by 10°.
-
Numerical Investigation of Engine Effects on a Transport Aircraft with Circulation Control
Journal of Aircraft, 2015Co-Authors: Dennis Keller, Ralf RudnikAbstract:The scope of this paper is to illustrate the installation effects of a turboprop engine on a high-lift configuration of a short takeoff and landing aircraft with Circulation Control. In addition to the influence on the wing performance, the impact on the longitudinal static stability of the aircraft is also investigated. Furthermore, critical failure cases, namely one engine inoperative, as well as an asymmetric Circulation Control failure, are assessed. Therefore, steady computational-fluid-dynamics calculations based on the Reynolds-averaged Navier–Stokes equations were performed. The propeller is modeled with an actuator-disk approach. The results show strong potential of increasing lift by synergy effects between Circulation Control and propeller slipstream. However, the longitudinal stability and Controllability are adversely affected. Regarding the case of one engine inoperative, the resulting yawing moments are twice as high as the actual yawing moments from the asymmetric thrust and are therefore ...
Chenliang Qiao - One of the best experts on this subject based on the ideXlab platform.
-
flow Control over the blunt trailing edge of wind turbine airfoils using Circulation Control
Energies, 2018Co-Authors: Heyong Xu, Chenliang Qiao, Qingli Dong, Zhengyin YeAbstract:A new partial Circulation Control (PCC) method is implemented on the blunt trailing edge DU97-Flatback airfoil, and compared with the traditional full Circulation Control (FCC) based on numerical analysis. When the Coanda jet is deactivated, PCC has an attractive advantage over FCC, since the design of PCC doesn’t degrade aerodynamic characteristics of the baseline flatback section, in contrast to FCC, which is important in practical use in case of failure of the Circulation Control system. When the Coanda jet is activated, PCC also outperforms FCC in several respects. PCC can produce much higher lift coefficients than FCC over the entire range of angles of attack as well as the entire range of jet momentum coefficients under investigation, but with slightly higher drag coefficients. The flow field of PCC is less complex than that of FCC, indicating less energy dissipation in the main flow and hence less power expenditure for the Coanda jet. The aerodynamic figure of merit (AFM) and Control efficiency for Circulation Control are defined, and results show that PCC has much higher AFM and Control efficiency than FCC. It is demonstrated that PCC outperforms FCC in terms of effectiveness, efficiency and reliability for flow Control in the blunt trailing edge wind turbine application.
-
active Circulation Control on the blunt trailing edge wind turbine airfoil
AIAA Journal, 2017Co-Authors: Heyong Xu, Chenliang Qiao, Huiqiang Yang, Zhengyin YeAbstract:Active Circulation Control on a thick blunt trailing edge wind turbine airfoil is proposed and numerically investigated by solving Reynolds-averaged Navier–Stokes equations along with Spalart–Allma...
Lijun You - One of the best experts on this subject based on the ideXlab platform.
-
mesoscopic structure characterization of plugging zone for lost Circulation Control in fractured reservoirs based on photoelastic experiment
Journal of Natural Gas Science and Engineering, 2020Co-Authors: Xiaopeng Yan, Lijun You, Xiangyu Shang, Haoran JingAbstract:Abstract Drilling fluid loss into formation fractures is one of the most common and costly problems encountered during the exploration and development of oil and gas resources. The stability of fracture plugging zone formed by lost Circulation materials has a great impact on the lost Circulation Control effect. Mesoscale structure stability of force chain, which is the way to transferring contact force between particles, determines the strength of the macroscale plugging zone. In the current paper, photoelastic method is introduced and photoelastic experimental system is developed to characterize the mesoscopic structure evolution of plugging zone under shear. The key parameters for the mesoscopic structure characterization of fracture plugging zone are proposed, including the proportion, distribution, elastic energy, and angle of the strong force chain. Experimental results show that the mesoscopic structure of plugging zone experiences continuous formation and destruction during the shear process. Initially, the distribution of the mesoscopic force chain under a vertical load presents a vertical tree branch structure. Then, the proportion of force chains in the horizontal direction increases and form a staggered network structure after a horizontal shear force is continuously applied. During the shear process of plugging zone, the mesoscopic force chain network experiences rearrangement and structural failure. The distribution density of elastic energy in the particles transferring strong force is reduced. Based on the developed photoelastic experimental system, the mesoscopic structure evolution of the plugging zone is accurately described. It can be used to guide the selection of the lost Circulation materials and optimization of the loss Control formula.
-
structural failure mechanism and strengthening method of fracture plugging zone for lost Circulation Control in deep naturally fractured reservoirs
Petroleum Exploration and Development, 2020Co-Authors: Xu Chengyuan, Xiaopeng Yan, Lijun You, Jingyi ZhangAbstract:Abstract Focused on the lost Circulation Control in deep naturally fractured reservoirs, the multiscale structure of fracture plugging zone is proposed based on the theory of granular matter mechanics, and the structural failure pattern of plugging zone is developed to reveal the plugging zone failure mechanisms in deep, high temperature, high pressure, and high in-situ stress environment. Based on the fracture plugging zone strength model, key performance parameters are determined for the optimal selection of loss Control material (LCM). Laboratory fracture plugging experiments with new LCM are carried out to evaluate the effect of the key performance parameters of LCM on fracture plugging quality. LCM selection strategy for fractured reservoirs is developed. The results show that the force chain formed by LCMs determines the pressure stabilization of macro-scale fracture plugging zone. Friction failure and shear failure are the two major failure patterns of fracture plugging zone. The strength of force chain depends on the performance of micro-scale LCM, and the LCM key performance parameters include particle size distribution, fiber aspect ratio, friction coefficient, compressive strength, soluble ability and high temperature resistance. Results of lab experiments and field test show that lost Circulation Control quality can be effectively improved with the optimal material selection based on the extracted key performance parameters of LCMs.
-
friction coefficient a significant parameter for lost Circulation Control and material selection in naturally fractured reservoir
Energy, 2019Co-Authors: Xiaopeng Yan, Lijun You, Zhenjiang You, Hao Zhang, Jingyi ZhangAbstract:Abstract Lost Circulation of working fluid into formation fractures is one of the most common and costly problems encountered during the development of petroleum and geothermal resources. Fracture plugging strength and efficiency with loss Control material determine the effect of lost Circulation Control. This paper proposes an integrated method for optimal material selection. The key mechanical parameter of loss Control material is determined based on mathematical model and simulation on fracture plugging strength and efficiency. The developed fracture plugging strength model accounts for the shear failure of fracture plugging zone. Simulation with coupled computational fluid dynamics and discrete element method is conducted for fracture plugging efficiency accounting for particles transport and capture in fracture. Model and simulation results show that friction coefficient is the key material mechanical parameter for fracture plugging effect. Laboratory experimental results show that rigid particle with lower roundness, fiber with higher tensile strength and elastic particle with higher deformation rate lead to larger friction coefficient and should be selected as loss Control material. Reasonable combination of rigid granule, fiber and elastic particle can create a synergistic effect to achieve the optimal friction coefficient and fracture plugging effect. Material selection strategy is determined and has been successfully applied to field case study in Sichuan Basin, China.
-
temporary sealing technology to Control formation damage induced by drill in fluid loss in fractured tight gas reservoir
Journal of Natural Gas Science and Engineering, 2014Co-Authors: Yili Kang, Lijun You, Dujie ZhangAbstract:Abstract Western Sichuan tight gas reservoir is characteristic of developed natural fractures and ultra low matrix permeability. Developed fractures are beneficial for the economic and efficient development of tight gas reservoir. But they will lead to lost Circulation of drill-in fluid and induce serious formation damage. Moreover, the dynamic fracture width which can reach several hundred microns or millimeter level resulting from drill-in fluid invasion increases the difficulty to solve the problem. To our best knowledge, few papers have been published on the technology that gives a synthetic consideration to both lost Circulation Control and formation damage prevention in fractured tight gas reservoir. In this paper, we develop the temporary sealing technology and propose its key indexes to Control drill-in loss in fractured reservoir. Laboratory experiments are conducted to determine the optimal material size, type and concentration to meet the index requirements. Maximum plugging pressure, total loss volume before sealing and permeability recovery rate are the three key indexes for the temporary sealing technology. Results of laboratory experiment considering the three indexes show that the D90 of the bridging particle size distribution should be equal to the maximum dynamic fracture width. The reasonable combination of rigid granule, fiber and elastic particle can create a synergy effect. The optimal concentration for rigid granule, fiber and elastic particle is 5.0%, 3.0% and 2.5% respectively. Based on the temporary sealing technology, the maximum plugging pressure and permeability recovery rate can be improved to 15.0 MPa and 88.6% respectively, and the total loss volume before sealing can be reduced to only 49 mL.