Abstract In this paper, a diffuser is used to integrate a transonic high-pressure turbine with a rotating detonation combustor (RDC). The paper focuses on the required design modifications to the turbine endwalls (EW) to enable high efficiency, while preserving the airfoil blade-to-blade geometry. The main challenge is the stator passage unstarting, due to the high inlet Mach number. First of all, steady Reynolds Averaged Navier Stokes simulations were performed to compare the efficiency of turbines with constant-radius EWs to turbines with axisymmetric EWs. A modified EW design prevented the unstarting of the stator passage, enabling a significant gain in performance. Afterward, the influence on the turbine efficiency and damping due to the unsteadiness from the diffuser-like fluctuations of the RDC was evaluated with unsteady Reynolds Averaged Navier Stokes simulations with a mixing plane approach (MPA). Full unsteady simulations were carried out on selected inlet conditions and compared to the mixing plane results. This parametric study provides turbine designers with recommended diffusion rates along the vane EWs. Additionally, we provide guidance on the upstream diffuser design, specifically the required damping and outlet Mach number.
{"title":"Integration of a transonic high-pressure turbine with a rotating detonation combustor and a diffuser","authors":"Zhe Liu, James Braun, Guillermo Paniagua","doi":"10.1515/tjj-2020-0016","DOIUrl":"https://doi.org/10.1515/tjj-2020-0016","url":null,"abstract":"Abstract In this paper, a diffuser is used to integrate a transonic high-pressure turbine with a rotating detonation combustor (RDC). The paper focuses on the required design modifications to the turbine endwalls (EW) to enable high efficiency, while preserving the airfoil blade-to-blade geometry. The main challenge is the stator passage unstarting, due to the high inlet Mach number. First of all, steady Reynolds Averaged Navier Stokes simulations were performed to compare the efficiency of turbines with constant-radius EWs to turbines with axisymmetric EWs. A modified EW design prevented the unstarting of the stator passage, enabling a significant gain in performance. Afterward, the influence on the turbine efficiency and damping due to the unsteadiness from the diffuser-like fluctuations of the RDC was evaluated with unsteady Reynolds Averaged Navier Stokes simulations with a mixing plane approach (MPA). Full unsteady simulations were carried out on selected inlet conditions and compared to the mixing plane results. This parametric study provides turbine designers with recommended diffusion rates along the vane EWs. Additionally, we provide guidance on the upstream diffuser design, specifically the required damping and outlet Mach number.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135031426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongxin Zhang, Jian-Jun Ye, Bo Jin, C. Xu, Guoping Huang
Abstract Endwall-pulsed blowing (EPB) is studied for three different excitation waveforms to improve the aerodynamic performance of highly loaded compressors. Some important excitation parameters include the excitation frequency and momentum coefficient, which were analyzed in detail. The results of the EPB are compared with the endwall steady blowing (ESB) case. For EPBs with the three excitation waveforms (Waveforms sine, triangle and trapezoid), excitation frequencies that are equal to an integral multiple of the natural frequency of the vortex shedding are optimal and provide better performances than the ESB with the same time-mean momentum coefficient. Moreover, the EPBs of the three excitation waveforms have significant differences in their aerodynamic performance improvements. The optimal case is achieved by the EPB with Waveform triangle and provides a total pressure loss coefficient with a reduction of 25.64%.
{"title":"Endwall-pulsed blowing of different excitation models to control flow separation on a highly-loaded compressor cascade","authors":"Hongxin Zhang, Jian-Jun Ye, Bo Jin, C. Xu, Guoping Huang","doi":"10.1515/tjj-2023-0009","DOIUrl":"https://doi.org/10.1515/tjj-2023-0009","url":null,"abstract":"Abstract Endwall-pulsed blowing (EPB) is studied for three different excitation waveforms to improve the aerodynamic performance of highly loaded compressors. Some important excitation parameters include the excitation frequency and momentum coefficient, which were analyzed in detail. The results of the EPB are compared with the endwall steady blowing (ESB) case. For EPBs with the three excitation waveforms (Waveforms sine, triangle and trapezoid), excitation frequencies that are equal to an integral multiple of the natural frequency of the vortex shedding are optimal and provide better performances than the ESB with the same time-mean momentum coefficient. Moreover, the EPBs of the three excitation waveforms have significant differences in their aerodynamic performance improvements. The optimal case is achieved by the EPB with Waveform triangle and provides a total pressure loss coefficient with a reduction of 25.64%.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44917768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract During take-off of a vertical take-off and landing (VTOL) aircraft, ground effects can cause a downward force on the aircraft body and wings. The downward force could substantially reduce the payload of the aircraft, which is undesirable. This paper investigates the ground effects related to VTOL applications with distributed propulsion. A slot jet is used to simulate the distributed propulsion system. A model of a wing with a slot jet placed near the trailing edge of the wing is investigated. The slot jet is almost perpendicular to the ground to provide a vertical thrust. Experimental and numerical methods are used to investigate the aerodynamic performance of this model. Theoretical analysis is carried out to understand the formation mechanism of the low pressure region on the lower surface of the wing, which causes the downward force. The flow physics of the jet inducing ground vortex is investigated. It is found that the convection term in the ground vortex area is the main source of the pressure reduction. Based on the flow mechanism, a redesigned configuration is proposed to reduce the negative effect of the ground vortex. The flow structures such as the tip vortex are also investigated.
{"title":"Ground effects on the aerodynamics of a wing with slot type distributed propulsion system for VTOL applications","authors":"Cheng'an Bai, Chao Zhou","doi":"10.1515/tjj-2022-0065","DOIUrl":"https://doi.org/10.1515/tjj-2022-0065","url":null,"abstract":"Abstract During take-off of a vertical take-off and landing (VTOL) aircraft, ground effects can cause a downward force on the aircraft body and wings. The downward force could substantially reduce the payload of the aircraft, which is undesirable. This paper investigates the ground effects related to VTOL applications with distributed propulsion. A slot jet is used to simulate the distributed propulsion system. A model of a wing with a slot jet placed near the trailing edge of the wing is investigated. The slot jet is almost perpendicular to the ground to provide a vertical thrust. Experimental and numerical methods are used to investigate the aerodynamic performance of this model. Theoretical analysis is carried out to understand the formation mechanism of the low pressure region on the lower surface of the wing, which causes the downward force. The flow physics of the jet inducing ground vortex is investigated. It is found that the convection term in the ground vortex area is the main source of the pressure reduction. Based on the flow mechanism, a redesigned configuration is proposed to reduce the negative effect of the ground vortex. The flow structures such as the tip vortex are also investigated.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45308044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract We propose a new type of effervescent atomizer with bushings installed in the liquid channel perpendicular to the channel’s axis. Bushings have holes through which air is injected to create bubbles. The air is released into the gap between the channel and the bushing. This investigation evaluates the bubbles’ atomization quality. Atomizer tests were conducted at multiple water and air flow rates, under different configurations, without an exit nozzle and with a 2 mm nozzle diameter. The atomizer’s design enables a homogenous bubble flow with small air bubbles. At an ALR = 0.012–0.036 and water flow rates of 1.67 and 2.17 L/min without an exit nozzle, bubble diameters of 0.2–0.4 mm comprised 40–50% of the total number of bubbles. The number of the bubbles with diameters of 0.8–1.0 mm does not exceed 5%. After increasing the injection parameter ε twice, the average diameter of the bubbles remained constant. Upon testing, an atomizer with one bushing, 2 mm-diameter outlet nozzle, and a water flow rate of 1.67 L/min produced particle diameters of SMD = 32–100 μm at ALR values of 0.02–0.12.
{"title":"Study of a new effervescent atomizer design","authors":"I. Levitsky, Nikolay Razoronov","doi":"10.1515/tjj-2023-0007","DOIUrl":"https://doi.org/10.1515/tjj-2023-0007","url":null,"abstract":"Abstract We propose a new type of effervescent atomizer with bushings installed in the liquid channel perpendicular to the channel’s axis. Bushings have holes through which air is injected to create bubbles. The air is released into the gap between the channel and the bushing. This investigation evaluates the bubbles’ atomization quality. Atomizer tests were conducted at multiple water and air flow rates, under different configurations, without an exit nozzle and with a 2 mm nozzle diameter. The atomizer’s design enables a homogenous bubble flow with small air bubbles. At an ALR = 0.012–0.036 and water flow rates of 1.67 and 2.17 L/min without an exit nozzle, bubble diameters of 0.2–0.4 mm comprised 40–50% of the total number of bubbles. The number of the bubbles with diameters of 0.8–1.0 mm does not exceed 5%. After increasing the injection parameter ε twice, the average diameter of the bubbles remained constant. Upon testing, an atomizer with one bushing, 2 mm-diameter outlet nozzle, and a water flow rate of 1.67 L/min produced particle diameters of SMD = 32–100 μm at ALR values of 0.02–0.12.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46471204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract We propose a new type of effervescent atomizer with bushings installed in the liquid channel perpendicular to the channel’s axis. Bushings have holes through which air is injected to create bubbles. The air is released into the gap between the channel and the bushing. This investigation evaluates the bubbles’ atomization quality. Atomizer tests were conducted at multiple water and air flow rates, under different configurations, without an exit nozzle and with a 2 mm nozzle diameter. The atomizer’s design enables a homogenous bubble flow with small air bubbles. At an ALR = 0.012–0.036 and water flow rates of 1.67 and 2.17 L/min without an exit nozzle, bubble diameters of 0.2–0.4 mm comprised 40–50% of the total number of bubbles. The number of the bubbles with diameters of 0.8–1.0 mm does not exceed 5%. After increasing the injection parameter ε twice, the average diameter of the bubbles remained constant. Upon testing, an atomizer with one bushing, 2 mm-diameter outlet nozzle, and a water flow rate of 1.67 L/min produced particle diameters of SMD = 32–100 μm at ALR values of 0.02–0.12.
{"title":"Study of a new effervescent atomizer design","authors":"I. Levitsky, Nikolay Razoronov","doi":"10.1515/tjeng-2023-0007","DOIUrl":"https://doi.org/10.1515/tjeng-2023-0007","url":null,"abstract":"Abstract We propose a new type of effervescent atomizer with bushings installed in the liquid channel perpendicular to the channel’s axis. Bushings have holes through which air is injected to create bubbles. The air is released into the gap between the channel and the bushing. This investigation evaluates the bubbles’ atomization quality. Atomizer tests were conducted at multiple water and air flow rates, under different configurations, without an exit nozzle and with a 2 mm nozzle diameter. The atomizer’s design enables a homogenous bubble flow with small air bubbles. At an ALR = 0.012–0.036 and water flow rates of 1.67 and 2.17 L/min without an exit nozzle, bubble diameters of 0.2–0.4 mm comprised 40–50% of the total number of bubbles. The number of the bubbles with diameters of 0.8–1.0 mm does not exceed 5%. After increasing the injection parameter ε twice, the average diameter of the bubbles remained constant. Upon testing, an atomizer with one bushing, 2 mm-diameter outlet nozzle, and a water flow rate of 1.67 L/min produced particle diameters of SMD = 32–100 μm at ALR values of 0.02–0.12.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44293875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The role of turbine blade cooling and coolants are significant factors in modern gas turbine aerodynamic design. This paper presents an effective and rapid airfoil design method based on CFD computation of the S1 surface and the existing loss correlations. The method can assess the coolant mixing loss by identifying each cooling hole separately and obtain the overall mainflow aerodynamic loss for cooled airfoil. The CFD computation code of the S1 surface is powered by a two-dimensional Euler equation, which is inviscid. Typical Kacker–Okapuu empirical correlations are then used to assess the airfoil friction loss, trailing edge loss, and shock loss. A novel form of the Hartsel model for coolant mixing loss is developed and employed in the CFD codes. In the reformed model, the mixing loss coefficient is directly associated with the blowing ratio and the total pressure/temperature ratio of mainstream-to-coolant, making it more convenient than the original model in the airfoil design process. Based on a transonic turbine vane airfoil, the influences of the film outflow location and outflow Mach number on the coolant mixing loss are investigated using the above prediction method and the cascade blowing test.
{"title":"A cooled turbine airfoil performance prediction method with two-dimensional CFD computation and loss models","authors":"Xiaodong Zhang, J. Liu, Chen Li","doi":"10.1515/tjj-2022-0044","DOIUrl":"https://doi.org/10.1515/tjj-2022-0044","url":null,"abstract":"Abstract The role of turbine blade cooling and coolants are significant factors in modern gas turbine aerodynamic design. This paper presents an effective and rapid airfoil design method based on CFD computation of the S1 surface and the existing loss correlations. The method can assess the coolant mixing loss by identifying each cooling hole separately and obtain the overall mainflow aerodynamic loss for cooled airfoil. The CFD computation code of the S1 surface is powered by a two-dimensional Euler equation, which is inviscid. Typical Kacker–Okapuu empirical correlations are then used to assess the airfoil friction loss, trailing edge loss, and shock loss. A novel form of the Hartsel model for coolant mixing loss is developed and employed in the CFD codes. In the reformed model, the mixing loss coefficient is directly associated with the blowing ratio and the total pressure/temperature ratio of mainstream-to-coolant, making it more convenient than the original model in the airfoil design process. Based on a transonic turbine vane airfoil, the influences of the film outflow location and outflow Mach number on the coolant mixing loss are investigated using the above prediction method and the cascade blowing test.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42550019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A full envelope LMI-based multi-region linear parameter-varying power controller is designed for a turbofan engine in this paper. According to the characteristics of aero-engine model, three scheduling variables are divided into two groups firstly, and then part of them are partitioned, rather than all scheduling variables are partitioned directly as the usual multi-region LPV control. The polynomial LPV model of aero-engine is established under a specific flight condition. An explicit LPV controller by gridding method based on parameter-dependent Lyapunov function is designed and we propose a method to eliminate the dependence of LPV controller on the derivative of scheduling parameter. The flight envelope of turbofan engine is divided into multiple sub-regions, and a mixing LPV control method with overlapping regions is proposed, which can guarantee stability and performance across the full envelope. Finally, the simulation results on the nonlinear component level model of a twin-spool turbofan engine verify our method.
{"title":"Gain scheduling control of aero-engine based on mixing polynomial LPV synthesis","authors":"Bin Shen, Lingfei Xiao, Zhuolin Ye","doi":"10.1515/tjj-2023-0001","DOIUrl":"https://doi.org/10.1515/tjj-2023-0001","url":null,"abstract":"Abstract A full envelope LMI-based multi-region linear parameter-varying power controller is designed for a turbofan engine in this paper. According to the characteristics of aero-engine model, three scheduling variables are divided into two groups firstly, and then part of them are partitioned, rather than all scheduling variables are partitioned directly as the usual multi-region LPV control. The polynomial LPV model of aero-engine is established under a specific flight condition. An explicit LPV controller by gridding method based on parameter-dependent Lyapunov function is designed and we propose a method to eliminate the dependence of LPV controller on the derivative of scheduling parameter. The flight envelope of turbofan engine is divided into multiple sub-regions, and a mixing LPV control method with overlapping regions is proposed, which can guarantee stability and performance across the full envelope. Finally, the simulation results on the nonlinear component level model of a twin-spool turbofan engine verify our method.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48043426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Starting from a component-level nonlinear model of a turboprop engine, the high-pressure turbine speed and power turbine speed output data at six steady-state operating points are linearized and fitted, and a turboprop engine state variable model is established. Based on these state variable models, the Proportional Integral Derivative (PID) control method, the augmented Linear Quadratic Regulator (LQR) control method and the Linear Quadratic Gaussian/Loop Transfer Recover (LQG/LTR) control method are used to design the controllers respectively, and the relative converted speed of the high-pressure turbine is selected as the scheduling parameter of the Linear Parameter Varying (LPV) model, and the controller is called to control the turboprop engine’s non-linear speed. Linear model for large envelope control. Finally, the control effects of the above three control methods are compared and analyzed, and their advantages and disadvantages are compared. The simulation results show that the LPV controller designed based on the LQG/LTR method is more effective than the controllers designed by the other two control methods on the nonlinear turboprop model.
{"title":"Research on turboprop engine control method based on linear parameter varying model","authors":"Liqiang He, Siyuan Li, Jiatong Du, Haibo Zhang","doi":"10.1515/tjj-2022-0075","DOIUrl":"https://doi.org/10.1515/tjj-2022-0075","url":null,"abstract":"Abstract Starting from a component-level nonlinear model of a turboprop engine, the high-pressure turbine speed and power turbine speed output data at six steady-state operating points are linearized and fitted, and a turboprop engine state variable model is established. Based on these state variable models, the Proportional Integral Derivative (PID) control method, the augmented Linear Quadratic Regulator (LQR) control method and the Linear Quadratic Gaussian/Loop Transfer Recover (LQG/LTR) control method are used to design the controllers respectively, and the relative converted speed of the high-pressure turbine is selected as the scheduling parameter of the Linear Parameter Varying (LPV) model, and the controller is called to control the turboprop engine’s non-linear speed. Linear model for large envelope control. Finally, the control effects of the above three control methods are compared and analyzed, and their advantages and disadvantages are compared. The simulation results show that the LPV controller designed based on the LQG/LTR method is more effective than the controllers designed by the other two control methods on the nonlinear turboprop model.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48785514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A 3D numerical analysis on an adiabatic flat plate for multi-hole trench cooling with forward, backward and mixed injection holes is performed in the current investigation. The numerical setup is validated before the performances of different cooling configurations are compared. The effect of three different multi-hole trench arrangements, square-diamond, long-diamond, and super-long-diamond with constant perforated percentage (3.27%), on film cooling performance is studied at blowing ratio 1.0. The row-to-row interaction between coolant jets and mainstream is analysed, and lateral film cooling effectiveness is calculated downstream. The dimensionless temperature contour overlaid with streamlines concluded that the SLD trench hole arrangement with forward injection forms a developed effusion layer due to counter-rotating vortex pairs, which helps in proper mixing of coolant jets into the mainstream and improves film cooling effectiveness in lateral as well as in longitudinal direction. It is observed that super-long-diamond arrangement with forward injection provides the highest film cooling effectiveness than square-diamond and long-diamond arrangements and favours early development of the coolant film layer.
{"title":"Effect of multi-hole trench cooling on an adiabatic flat plate for gas turbine application","authors":"Ved Prakash, S. Chandel, D. Thakur, Ranjan Mishra","doi":"10.1515/tjj-2022-0061","DOIUrl":"https://doi.org/10.1515/tjj-2022-0061","url":null,"abstract":"Abstract A 3D numerical analysis on an adiabatic flat plate for multi-hole trench cooling with forward, backward and mixed injection holes is performed in the current investigation. The numerical setup is validated before the performances of different cooling configurations are compared. The effect of three different multi-hole trench arrangements, square-diamond, long-diamond, and super-long-diamond with constant perforated percentage (3.27%), on film cooling performance is studied at blowing ratio 1.0. The row-to-row interaction between coolant jets and mainstream is analysed, and lateral film cooling effectiveness is calculated downstream. The dimensionless temperature contour overlaid with streamlines concluded that the SLD trench hole arrangement with forward injection forms a developed effusion layer due to counter-rotating vortex pairs, which helps in proper mixing of coolant jets into the mainstream and improves film cooling effectiveness in lateral as well as in longitudinal direction. It is observed that super-long-diamond arrangement with forward injection provides the highest film cooling effectiveness than square-diamond and long-diamond arrangements and favours early development of the coolant film layer.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41468604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The complex vortex structure compressor leads to the problem that the transition model is insufficient in predicting the flow instability of the compressor. In this paper, the rectangular cascade of compressor of different turning-angle conditions is taken as the object, and the transition characteristics on the end wall and the blade surface of the compressor cascade are in comparison by the method of large eddy simulation/LES. The effects of the horseshoe vortex and the separation bubble over the compressor cascade on the transition process are emphatically discussed. By analyzing characteristic parameters of the vortex structure, it is found that the separated transitional flow corresponds to multiple separations-and reattachments of the shedding vortex, and is affected by the cross-flow transition and the separate-transition. Finally, by discussing the instability of the separation line, reattachment line and the cross-flow inflection point of the separated transitional flow, it reveals that the transient disturbance caused by the vortex motion is an important reason affecting the prediction accuracy of the transition model.
{"title":"Numerical study of transition process in different zones of a compressor cascade channel","authors":"Xiang Li, Q. Zheng, Hefei Li, Wei Yan, B. Jiang","doi":"10.1515/tjj-2022-0084","DOIUrl":"https://doi.org/10.1515/tjj-2022-0084","url":null,"abstract":"Abstract The complex vortex structure compressor leads to the problem that the transition model is insufficient in predicting the flow instability of the compressor. In this paper, the rectangular cascade of compressor of different turning-angle conditions is taken as the object, and the transition characteristics on the end wall and the blade surface of the compressor cascade are in comparison by the method of large eddy simulation/LES. The effects of the horseshoe vortex and the separation bubble over the compressor cascade on the transition process are emphatically discussed. By analyzing characteristic parameters of the vortex structure, it is found that the separated transitional flow corresponds to multiple separations-and reattachments of the shedding vortex, and is affected by the cross-flow transition and the separate-transition. Finally, by discussing the instability of the separation line, reattachment line and the cross-flow inflection point of the separated transitional flow, it reveals that the transient disturbance caused by the vortex motion is an important reason affecting the prediction accuracy of the transition model.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48238318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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