Zhiyuan Cao, Chuxuan Wang, Jiantong Zhao, Xinyu Hao, Zhigao Song, Bo Liu
Abstract Upstream vortex has a significant effect on the secondary flow structure of the downstream turbine in the stage environment. This study investigates the secondary flow structure with non-axisymmetric endwall profiling (NAEW) under the interaction of co-rotating incoming vortex (Vic). A half-delta wing vortex generator is utilized to model Vic. The turbine cascade case which exhibited maximum reduction of the cascade loss with NAEW under no incoming vortex is studied. The mechanism of loss reduction with NAEW under the interaction of Vic is analysed. Vic could decrease the secondary flow near the endwall region by affecting the horseshoe vortex transport in the cascade. However, its loss reduction was lower than the loss increments of Vic itself. The arrival of Vic at the leading edge of the cascade increased the strength of the horseshoe vortex, resulting in a significant increase in loss. Under the interaction of Vic, NAEW decreased the blade loading near endwall region, which resulted in the reduction of cascade loss.
{"title":"Control mechanism of secondary flow in a turbine cascade with non-axisymmetric endwall profiling under Co-rotating incoming vortex","authors":"Zhiyuan Cao, Chuxuan Wang, Jiantong Zhao, Xinyu Hao, Zhigao Song, Bo Liu","doi":"10.1515/tjj-2022-0063","DOIUrl":"https://doi.org/10.1515/tjj-2022-0063","url":null,"abstract":"Abstract Upstream vortex has a significant effect on the secondary flow structure of the downstream turbine in the stage environment. This study investigates the secondary flow structure with non-axisymmetric endwall profiling (NAEW) under the interaction of co-rotating incoming vortex (Vic). A half-delta wing vortex generator is utilized to model Vic. The turbine cascade case which exhibited maximum reduction of the cascade loss with NAEW under no incoming vortex is studied. The mechanism of loss reduction with NAEW under the interaction of Vic is analysed. Vic could decrease the secondary flow near the endwall region by affecting the horseshoe vortex transport in the cascade. However, its loss reduction was lower than the loss increments of Vic itself. The arrival of Vic at the leading edge of the cascade increased the strength of the horseshoe vortex, resulting in a significant increase in loss. Under the interaction of Vic, NAEW decreased the blade loading near endwall region, which resulted in the reduction of cascade loss.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44895743","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}
Yue Zhou, Jie Wu, Weibang He, Jing Ma, Pengcheng Qi, Liang Li
Abstract As an inner heat source, the propulsion system of aircraft obviously influences the rear fuselage thermal status and thus produced infrared signature. In this paper, a coupled flow-heat simulation method is established to calculate the inner and outer flow fields of a realistic aircraft exhaust system. Considering multi heat transfer modes and fluid-solid thermal interactions, the method is examined by available experimental data. Different nozzle layouts are then provided to analyse the influence of inner hot parts including combustion gas and solid walls on the outer fuselage temperature changes. Thermal radiation is individually researched and analysed since radiation flux heats the outer fuselage skin significantly, especially in the cold convection channel. The simulation results indicate that the appearance of intermediate shield device effectively suppresses the outer fuselage temperature-rise and therefore resulting infrared signatures. In comparison, the exhaust system equipped with intermediate shield could decrease outer fuselage infrared signatures by 69 and 40% for 3–5 μm band and 8–12 μm band, respectively.
{"title":"Infrared simulation of aircraft rear fuselage based on a coupled CFD method","authors":"Yue Zhou, Jie Wu, Weibang He, Jing Ma, Pengcheng Qi, Liang Li","doi":"10.1515/tjj-2022-0081","DOIUrl":"https://doi.org/10.1515/tjj-2022-0081","url":null,"abstract":"Abstract As an inner heat source, the propulsion system of aircraft obviously influences the rear fuselage thermal status and thus produced infrared signature. In this paper, a coupled flow-heat simulation method is established to calculate the inner and outer flow fields of a realistic aircraft exhaust system. Considering multi heat transfer modes and fluid-solid thermal interactions, the method is examined by available experimental data. Different nozzle layouts are then provided to analyse the influence of inner hot parts including combustion gas and solid walls on the outer fuselage temperature changes. Thermal radiation is individually researched and analysed since radiation flux heats the outer fuselage skin significantly, especially in the cold convection channel. The simulation results indicate that the appearance of intermediate shield device effectively suppresses the outer fuselage temperature-rise and therefore resulting infrared signatures. In comparison, the exhaust system equipped with intermediate shield could decrease outer fuselage infrared signatures by 69 and 40% for 3–5 μm band and 8–12 μm band, respectively.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46552075","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}
Yang Yong, Fu Yaoming, Lin Binbin, Hou Kuanxin, Kong Ling Bing, X. Honghui, Gao Jie, Jiang Shiqi
Abstract In order to improve the effectiveness of compressor efficiency measurement results under the influence of complex factors, several research work have been carried out, such as inverse connection of thermocouple suitable for efficiency measurement under low pressure ratio and small temperature rise conditions, torque efficiency correction considering the mechanical loss of high speed gearbox under various working conditions, and identification of the impact of seal cavity leakage flow on efficiency measurement. Compared with the conventional connection method of thermocouple, the inverse connection method of thermocouple shows obvious advantages in efficiency measurement under low pressure ratio and small temperature rise conditions. At medium and low speeds, the conventional simplified correction method will lead to the high measurement results of torque efficiency after installing the high speed gearbox. The accuracy of torque efficiency measurement can be improved by adopting the improved correction method. Increasing the oil supply pressure of the high speed gearbox or reducing the oil supply temperature will increase the mechanical loss of the high speed gearbox. The air flow in the compressor bearing seal chamber will leak into the flow passage through the labyrinth clearance, resulting in discontinuous changes of the inlet/outlet flow of compressor.
{"title":"Accurate measurement and evaluation method of axial compressor efficiency under the influence of multiple factors","authors":"Yang Yong, Fu Yaoming, Lin Binbin, Hou Kuanxin, Kong Ling Bing, X. Honghui, Gao Jie, Jiang Shiqi","doi":"10.1515/tjj-2022-0054","DOIUrl":"https://doi.org/10.1515/tjj-2022-0054","url":null,"abstract":"Abstract In order to improve the effectiveness of compressor efficiency measurement results under the influence of complex factors, several research work have been carried out, such as inverse connection of thermocouple suitable for efficiency measurement under low pressure ratio and small temperature rise conditions, torque efficiency correction considering the mechanical loss of high speed gearbox under various working conditions, and identification of the impact of seal cavity leakage flow on efficiency measurement. Compared with the conventional connection method of thermocouple, the inverse connection method of thermocouple shows obvious advantages in efficiency measurement under low pressure ratio and small temperature rise conditions. At medium and low speeds, the conventional simplified correction method will lead to the high measurement results of torque efficiency after installing the high speed gearbox. The accuracy of torque efficiency measurement can be improved by adopting the improved correction method. Increasing the oil supply pressure of the high speed gearbox or reducing the oil supply temperature will increase the mechanical loss of the high speed gearbox. The air flow in the compressor bearing seal chamber will leak into the flow passage through the labyrinth clearance, resulting in discontinuous changes of the inlet/outlet flow of compressor.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45737486","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}
Dai Yuchen, Song Manxiang, Jin Donghai, G. Xingmin, Liu Xiaoheng
Abstract Since Professor Greziter first proposed a theoretical model to predict the dynamic behavior of a compression system in 1976, the contribution of the volume effect to compressor flow instabilities has been widely studied, but the role of volume effect on the compressor performance during acceleration and deceleration has not received much attention. Therefore, starting from the Greitzer lumped parameter approach and integrating with real engine simulated components to improve the Greitzer’s model, an engine transient simulation model accounting for the compressor volume effect (referred to as the unsteady model) is developed in this paper. Based on a real turbofan engine, transient examination comprising acceleration and deceleration has been conducted for the validation of the unsteady model. The simulation results show better agreement with the experimental data compared with the transient simulation without considering the compressor volume effect (referred to as the quasi-steady model), which confirms the importance of introducing the compressor volume effect into the engine transient modeling. And the cause of the deviation between unsteady model and quasi-steady model are further explained by the compressor inlet and outlet mass flow curve. The results may further contribute to the development of engine transient model.
{"title":"Modeling and validation of the volume effect on the axial fan transient performance","authors":"Dai Yuchen, Song Manxiang, Jin Donghai, G. Xingmin, Liu Xiaoheng","doi":"10.1515/tjj-2022-0053","DOIUrl":"https://doi.org/10.1515/tjj-2022-0053","url":null,"abstract":"Abstract Since Professor Greziter first proposed a theoretical model to predict the dynamic behavior of a compression system in 1976, the contribution of the volume effect to compressor flow instabilities has been widely studied, but the role of volume effect on the compressor performance during acceleration and deceleration has not received much attention. Therefore, starting from the Greitzer lumped parameter approach and integrating with real engine simulated components to improve the Greitzer’s model, an engine transient simulation model accounting for the compressor volume effect (referred to as the unsteady model) is developed in this paper. Based on a real turbofan engine, transient examination comprising acceleration and deceleration has been conducted for the validation of the unsteady model. The simulation results show better agreement with the experimental data compared with the transient simulation without considering the compressor volume effect (referred to as the quasi-steady model), which confirms the importance of introducing the compressor volume effect into the engine transient modeling. And the cause of the deviation between unsteady model and quasi-steady model are further explained by the compressor inlet and outlet mass flow curve. The results may further contribute to the development of engine transient model.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41744324","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 This work presents an approach for sensitivity analysis of turbine cooling blade with surface thickness uncertainties, combining mesh deformation method, neural network model and multidisciplinary analysis. Normally, for even tiny shape changes, conventional geometry-based method failed easily during the auto-processing analysis. Therefore, mesh deformation method was utilized to capture the tiny size changes in the multidisciplinary analysis for both the fluid and the structure meshes. The neural network model is constructed by design of experiments to reduce the computational cost. Sensitivity analysis of the multidisciplinary system of blade is performed by numerical difference algorithm with the neural network model. Results showed that the proposed method was effective and practical in engineering.
{"title":"Multidisciplinary sensitivity analysis for turbine blade considering thickness uncertainties","authors":"Fan Yang, Chunyu Zhang, W. Gao, Lei Li","doi":"10.1515/tjeng-2022-0034","DOIUrl":"https://doi.org/10.1515/tjeng-2022-0034","url":null,"abstract":"Abstract This work presents an approach for sensitivity analysis of turbine cooling blade with surface thickness uncertainties, combining mesh deformation method, neural network model and multidisciplinary analysis. Normally, for even tiny shape changes, conventional geometry-based method failed easily during the auto-processing analysis. Therefore, mesh deformation method was utilized to capture the tiny size changes in the multidisciplinary analysis for both the fluid and the structure meshes. The neural network model is constructed by design of experiments to reduce the computational cost. Sensitivity analysis of the multidisciplinary system of blade is performed by numerical difference algorithm with the neural network model. Results showed that the proposed method was effective and practical in engineering.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47575022","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}
Fuzhou Liu, Huacheng Yuan, Jun Liu, Lingfeng Xu, Zhenggui Zhou
Abstract Based on the flow field characteristics of the missile body, an integrated design method for missile and inlet with two side layout is proposed under asymmetric inflow. The result of numerical simulation shows that shock waves hit on cowl lip on the symmetry plane at the design condition, which verifies the method of integrated design. And the flow characteristics of inlet under the influence of the missile body are analyzed. Under the influence of asymmetric incoming flow and missile body, the first shock wave surface of the two-dimensional inlet presents the characteristics of a three-dimensional concave surface, and there is a pair of asymmetric vortex structures in the inner flow path. Finally, a bleed cavity of self-adaptively adjusting bleeding by vortex is proposed to improve the performance of inlet and broaden the inlet start and attack angle boundary. The minimum Mach number of the inlet start is reduced from 2.8 to 2.3 at ɑ = 6° and the maximum attack angle of inlet start is widened from ɑ = −1° to ɑ = 3° at Ma = 2.1.
{"title":"Integrated design and analysis of inlet and missile with two side layout","authors":"Fuzhou Liu, Huacheng Yuan, Jun Liu, Lingfeng Xu, Zhenggui Zhou","doi":"10.1515/tjj-2022-0076","DOIUrl":"https://doi.org/10.1515/tjj-2022-0076","url":null,"abstract":"Abstract Based on the flow field characteristics of the missile body, an integrated design method for missile and inlet with two side layout is proposed under asymmetric inflow. The result of numerical simulation shows that shock waves hit on cowl lip on the symmetry plane at the design condition, which verifies the method of integrated design. And the flow characteristics of inlet under the influence of the missile body are analyzed. Under the influence of asymmetric incoming flow and missile body, the first shock wave surface of the two-dimensional inlet presents the characteristics of a three-dimensional concave surface, and there is a pair of asymmetric vortex structures in the inner flow path. Finally, a bleed cavity of self-adaptively adjusting bleeding by vortex is proposed to improve the performance of inlet and broaden the inlet start and attack angle boundary. The minimum Mach number of the inlet start is reduced from 2.8 to 2.3 at ɑ = 6° and the maximum attack angle of inlet start is widened from ɑ = −1° to ɑ = 3° at Ma = 2.1.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46722241","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 To solve the poor precision and low efficiency of manual grinding de-weight dynamic balance of turbopump rotor, the laser de-weight dynamic balance technology of rotating machines is adopted. Combined with the advantages of laser de-weight, such as, fast processing speed high machining precision and good machined surface quality, the smooth transition of the machined surface was realized by means of hierarchical machining. According to the characteristics of the turbopump rotor structure, the equivalent transformation model for laser de-weight turbopump rotor was built to convert the unbalance into laser processing parameters, which achieve the rapid and accurate de-weight of turbopump rotor. It focuses on solving the repeatedly loading and low accuracy of manual grinding dynamic balance. To verify the effectiveness of the proposed technique, laser de-weight experiments were carried out on two turbopump rotor test pieces. A dynamic balance test bench was set up to measure the rotor residual unbalance at 1800 r/min test speed, which is low dynamic balance. The results show that the machined surface transition was smooth, the residual unbalance was small and the machining efficiency was high. The effect of laser de-weight dynamic balance reached the expectation. It is an universal technology which is not limited to the dynamic balance of turbopump rotor, but also applicable to other rotating machinery..
{"title":"Study on laser de-weight and dynamic balance technology of rotating machines","authors":"Zhifu Tan, Lidong He, Chu-quan Deng, Yipeng Zhang, Xinyun Jia","doi":"10.1515/tjj-2022-0026","DOIUrl":"https://doi.org/10.1515/tjj-2022-0026","url":null,"abstract":"Abstract To solve the poor precision and low efficiency of manual grinding de-weight dynamic balance of turbopump rotor, the laser de-weight dynamic balance technology of rotating machines is adopted. Combined with the advantages of laser de-weight, such as, fast processing speed high machining precision and good machined surface quality, the smooth transition of the machined surface was realized by means of hierarchical machining. According to the characteristics of the turbopump rotor structure, the equivalent transformation model for laser de-weight turbopump rotor was built to convert the unbalance into laser processing parameters, which achieve the rapid and accurate de-weight of turbopump rotor. It focuses on solving the repeatedly loading and low accuracy of manual grinding dynamic balance. To verify the effectiveness of the proposed technique, laser de-weight experiments were carried out on two turbopump rotor test pieces. A dynamic balance test bench was set up to measure the rotor residual unbalance at 1800 r/min test speed, which is low dynamic balance. The results show that the machined surface transition was smooth, the residual unbalance was small and the machining efficiency was high. The effect of laser de-weight dynamic balance reached the expectation. It is an universal technology which is not limited to the dynamic balance of turbopump rotor, but also applicable to other rotating machinery..","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46250170","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 Flutter-induced fatigue failure investigation of the fan blades of aero-engines necessitates extensive testing. During engine ground testing, strain gauges on rotor fan blades and casing vibration sensors were employed to investigate structural dynamic aspects. The correlation between strain sensor signals and fan casing vibration signals allowed the diagnosis of fluttering fan blades. For automated flutter detection during engine development testing, a machine learning-augmented information fusion methodology was developed. The method analyses casing vibration signals by extracting time-domain statistical features, intrinsic mode function characteristics through empirical mode decomposition, and recurrence quantification features. Feature vectors obtained from a relatively large set of engine tests were subjected to dimension reduction by applying machine learning techniques to rank them. Reduced feature vector space was labelled as “flutter” or “normal” based on the correlation of rotor strain gauge signals. In addition, the labelled feature vectors were employed to train classifier models using supervised learning-based algorithms such as Support Vector Machines, Linear Discriminant Analysis, K-means Clustering, and Artificial Neural Networks. Using only vibration signals from the casing, the trained and validated classifiers were able to detect flutter in fan baldes with a 99% probability during subsequent testing.
{"title":"Machine learning augmented multi-sensor data fusion to detect aero engine fan rotor blade flutter","authors":"A. Rao, T. Satish, V. Naidu, Soumendu Jana","doi":"10.1515/tjj-2022-0066","DOIUrl":"https://doi.org/10.1515/tjj-2022-0066","url":null,"abstract":"Abstract Flutter-induced fatigue failure investigation of the fan blades of aero-engines necessitates extensive testing. During engine ground testing, strain gauges on rotor fan blades and casing vibration sensors were employed to investigate structural dynamic aspects. The correlation between strain sensor signals and fan casing vibration signals allowed the diagnosis of fluttering fan blades. For automated flutter detection during engine development testing, a machine learning-augmented information fusion methodology was developed. The method analyses casing vibration signals by extracting time-domain statistical features, intrinsic mode function characteristics through empirical mode decomposition, and recurrence quantification features. Feature vectors obtained from a relatively large set of engine tests were subjected to dimension reduction by applying machine learning techniques to rank them. Reduced feature vector space was labelled as “flutter” or “normal” based on the correlation of rotor strain gauge signals. In addition, the labelled feature vectors were employed to train classifier models using supervised learning-based algorithms such as Support Vector Machines, Linear Discriminant Analysis, K-means Clustering, and Artificial Neural Networks. Using only vibration signals from the casing, the trained and validated classifiers were able to detect flutter in fan baldes with a 99% probability during subsequent testing.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42454644","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}
Jai Bhan Verma, Mohan Agrawal, G. Joshi, S. Chandel, Ved Prakash, R. K. Mishra
Abstract The present study reports the numerical investigation of the compressor cascade. To minimize the separation phenomenon in the compressor cascade, a passive flow control device i.e. Micro Vortex Generator (MVG) is utilized. MVG is a very simple and lightweight attachment mounted infront of the leading edge of the cascade blade. Due to being passive in nature, it neither consumes power nor requires any external device to actuate. The numerical simulations were carried out on a highly loaded compressor cascade at an angle of incidence of −1° under subsonic conditions at Mach number 0.2. The profile of the compressor cascade blade was double circular arc (DCA), unsymmetrical and cambered at 40°. Two different types of micro vortex generators were mounted infront of the leading edge in the compressor cascade to control the secondary flows since secondary flows were responsible for various losses in cascade. To analyze the flow under incompressoible state of air (M = 0.2), Star CCM + software has been used. To simulate the flow under turbulent condition, k-ω SST turbulence model was used. A velocity profile of 25 mm boundary layer thickness was extracted and used as an input in the compressor cascade. Mounting of MVG on compressor cascade enhanced drag but also increased lift. Total pressure loss coefficient (TPLC) was calculated to compare the losses. The aerodynamic efficiency in terms of coefficient of lift and coefficient of drag has been used to study the effect of MVG over cascade. It is found that there is reduction in total pressure loss coefficient (TPLC) for trapezoidal and curved trapezoidal types of MVGs and the decrease in percentage are 2.17 and 8.86%, respectively. Alos, aerodynamic efficiency is increased by mounting trapezoidal and curved trapezoidal types of MVG and the increase in percentages are 2.03 and 3.10%, respectively.
{"title":"CFD analysis of flow control in compressor cascade using MVGs","authors":"Jai Bhan Verma, Mohan Agrawal, G. Joshi, S. Chandel, Ved Prakash, R. K. Mishra","doi":"10.1515/tjj-2022-0046","DOIUrl":"https://doi.org/10.1515/tjj-2022-0046","url":null,"abstract":"Abstract The present study reports the numerical investigation of the compressor cascade. To minimize the separation phenomenon in the compressor cascade, a passive flow control device i.e. Micro Vortex Generator (MVG) is utilized. MVG is a very simple and lightweight attachment mounted infront of the leading edge of the cascade blade. Due to being passive in nature, it neither consumes power nor requires any external device to actuate. The numerical simulations were carried out on a highly loaded compressor cascade at an angle of incidence of −1° under subsonic conditions at Mach number 0.2. The profile of the compressor cascade blade was double circular arc (DCA), unsymmetrical and cambered at 40°. Two different types of micro vortex generators were mounted infront of the leading edge in the compressor cascade to control the secondary flows since secondary flows were responsible for various losses in cascade. To analyze the flow under incompressoible state of air (M = 0.2), Star CCM + software has been used. To simulate the flow under turbulent condition, k-ω SST turbulence model was used. A velocity profile of 25 mm boundary layer thickness was extracted and used as an input in the compressor cascade. Mounting of MVG on compressor cascade enhanced drag but also increased lift. Total pressure loss coefficient (TPLC) was calculated to compare the losses. The aerodynamic efficiency in terms of coefficient of lift and coefficient of drag has been used to study the effect of MVG over cascade. It is found that there is reduction in total pressure loss coefficient (TPLC) for trapezoidal and curved trapezoidal types of MVGs and the decrease in percentage are 2.17 and 8.86%, respectively. Alos, aerodynamic efficiency is increased by mounting trapezoidal and curved trapezoidal types of MVG and the increase in percentages are 2.03 and 3.10%, respectively.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49510946","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 quantitative study is carried out to explore the air/mist-coupled cooling in the cooling section incorporating a spray device, aiming to conduct a comparative simulation on the effects of two radial spray arrangements (Apparatus A and Apparatus B) on the change of flow field. The results show that an even spray arrangement leads to improved flow performance owing to the large temperature drop in the cooling section. Compared with Apparatus A, Apparatus B enables a 1.60–2.25% higher temperature drop coefficient and a 1.1–3.0% higher water evaporation rate. Six high-altitude conditions are simulated to find that the spray device and water injection are the main factors causing flow loss, whereas the additional mass flow caused by water vapor reduces the amount of loss. The highest temperature drop coefficient is observed for Case 6 (27.3%), in which there is a more uniform nozzle arrangement. A slight difference in terms of total pressure drop coefficient between Apparatus A and Apparatus B is observed. Moreover, the highest total pressure drop coefficient (5.8%) at the location of the spray system is observed for Case 6, which has the largest injection rate and highest inlet air Mach number.
{"title":"Quantitative investigation of the evaporation and resistance characteristics of inlet jet precooling","authors":"Yuming Lu, Hongzi Fei, Hao Yang, Hai Zhang","doi":"10.1515/tjj-2021-0035","DOIUrl":"https://doi.org/10.1515/tjj-2021-0035","url":null,"abstract":"Abstract A quantitative study is carried out to explore the air/mist-coupled cooling in the cooling section incorporating a spray device, aiming to conduct a comparative simulation on the effects of two radial spray arrangements (Apparatus A and Apparatus B) on the change of flow field. The results show that an even spray arrangement leads to improved flow performance owing to the large temperature drop in the cooling section. Compared with Apparatus A, Apparatus B enables a 1.60–2.25% higher temperature drop coefficient and a 1.1–3.0% higher water evaporation rate. Six high-altitude conditions are simulated to find that the spray device and water injection are the main factors causing flow loss, whereas the additional mass flow caused by water vapor reduces the amount of loss. The highest temperature drop coefficient is observed for Case 6 (27.3%), in which there is a more uniform nozzle arrangement. A slight difference in terms of total pressure drop coefficient between Apparatus A and Apparatus B is observed. Moreover, the highest total pressure drop coefficient (5.8%) at the location of the spray system is observed for Case 6, which has the largest injection rate and highest inlet air Mach number.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49229658","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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