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":" ","pages":""},"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":" ","pages":""},"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":" ","pages":""},"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":" ","pages":""},"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}
Naren Shankar Radha Krishnan, Sathish Kumar Sarath Kumar, Vijayaraja Kengaiah, S. Chidambaram, E. Rathakrishnan
Abstract The characteristics of a sonic under-expanded coaxial jet with lip thickness 1.5D p (where D p is the exit diameter of primary jet equals 10 mm) with the primary jet operating at nozzle pressure ratio (NPR) of 3, 4 and 5. For NPR 3 operating primary jet, the secondary jet operates at NPR 2.5, 1.4 and 1.27. For primary jet NPR 4, the secondary jet operating NPR is 3.2, 1.6 and 1.4. For NPR 5 primary jet, the secondary jet NPR is 3.8, 1.89 and 1.52. The study is performed using a co-flow nozzle of bypass ratio (BR) 6.4, 1.4 and 0.7. The core length of the primary jet is used as a measure to quantify the mixing of the primary jet in the presence of coaxial jet. The shock structure present in the near field was viewed using shadowgraph technique. Centreline pitot pressure distribution, radial spread and waves present in the jet core were analyzed. The results show that the mixing associated with the high bypass coaxial jet is superior to the low bypass coaxial jet. This mixing superiority associated with high bypass coaxial jet prevails all levels of expansion.
{"title":"Effect of bypass ratio on sonic underexpanded co-flow jets with finite lip thickness","authors":"Naren Shankar Radha Krishnan, Sathish Kumar Sarath Kumar, Vijayaraja Kengaiah, S. Chidambaram, E. Rathakrishnan","doi":"10.1515/tjj-2022-0068","DOIUrl":"https://doi.org/10.1515/tjj-2022-0068","url":null,"abstract":"Abstract The characteristics of a sonic under-expanded coaxial jet with lip thickness 1.5D p (where D p is the exit diameter of primary jet equals 10 mm) with the primary jet operating at nozzle pressure ratio (NPR) of 3, 4 and 5. For NPR 3 operating primary jet, the secondary jet operates at NPR 2.5, 1.4 and 1.27. For primary jet NPR 4, the secondary jet operating NPR is 3.2, 1.6 and 1.4. For NPR 5 primary jet, the secondary jet NPR is 3.8, 1.89 and 1.52. The study is performed using a co-flow nozzle of bypass ratio (BR) 6.4, 1.4 and 0.7. The core length of the primary jet is used as a measure to quantify the mixing of the primary jet in the presence of coaxial jet. The shock structure present in the near field was viewed using shadowgraph technique. Centreline pitot pressure distribution, radial spread and waves present in the jet core were analyzed. The results show that the mixing associated with the high bypass coaxial jet is superior to the low bypass coaxial jet. This mixing superiority associated with high bypass coaxial jet prevails all levels of expansion.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41946926","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}
Kuanxin Hou, H. Xiang, Jie Gao, Binbin Lin, Qiulin Dai, Yao Fu, Yong Yang, Lei Huang
Abstract Aiming at the problem of aerodynamic coupling interference between disturbance of the built-in measurement probe and internal flow of high load compressor, the experiment of axial position and structure dimension of cylindrical probe support effect on the performance of the compressor cascade was carried out on the transonic plane cascade test facility. The effect characteristics of the distribution of probe support on aerodynamic performance of downstream cascade under different inlet Mach numbers were analyzed through the experimental data. The experimental results show that the axial position of probe support has little impact on the total pressure loss coefficient of cascade under the low-speed inlet flow condition. However, the variety of the axial position of probe support has a great impact on the total pressure loss coefficient of cascade under the high-speed inlet flow condition. With the decrease of the axial distance between probe support and cascade, the total pressure loss coefficient of cascade increases. Under different inlet flow conditions, the variety of the structure dimension of probe support has a significant impact on the total pressure loss coefficient of cascade. With the increase of the structure dimension of probe support, the total pressure loss coefficient of cascade increases.
{"title":"Effect of the distribution of the upstream probe support on performance of compressor cascade","authors":"Kuanxin Hou, H. Xiang, Jie Gao, Binbin Lin, Qiulin Dai, Yao Fu, Yong Yang, Lei Huang","doi":"10.1515/tjeng-2022-0027","DOIUrl":"https://doi.org/10.1515/tjeng-2022-0027","url":null,"abstract":"Abstract Aiming at the problem of aerodynamic coupling interference between disturbance of the built-in measurement probe and internal flow of high load compressor, the experiment of axial position and structure dimension of cylindrical probe support effect on the performance of the compressor cascade was carried out on the transonic plane cascade test facility. The effect characteristics of the distribution of probe support on aerodynamic performance of downstream cascade under different inlet Mach numbers were analyzed through the experimental data. The experimental results show that the axial position of probe support has little impact on the total pressure loss coefficient of cascade under the low-speed inlet flow condition. However, the variety of the axial position of probe support has a great impact on the total pressure loss coefficient of cascade under the high-speed inlet flow condition. With the decrease of the axial distance between probe support and cascade, the total pressure loss coefficient of cascade increases. Under different inlet flow conditions, the variety of the structure dimension of probe support has a significant impact on the total pressure loss coefficient of cascade. With the increase of the structure dimension of probe support, the total pressure loss coefficient of cascade increases.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41446578","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}
Q. Wang, Zhourong Zhang, Shuning Xiao, Qingsong Hong
Abstract The variations of inlet environment parameters can make significant effects on the compressor performance. This paper aims to investigate the effects of inlet total pressure and total temperature changes on the rated condition performance of a nine-stage HPC. Different cases of total pressure and total temperature boundary conditions at this compressor inlet are studied by 3-D numerical simulations with experimental validations. The numerical results confirm that the variations of inlet total pressure and total temperature make different effects on the rated condition performance of compressor. The overall performance parameters, such as the corrected mass flow and isentropic efficiency, will increase with inlet total pressure increasing and decrease with inlet total temperature increasing by different change rules. The flow similarity is also investigated by comparing the calculated results of critical quantities in different cases. The results indicate that the rising inlet total pressure can increase the Reynolds number and it is beneficial to reduce the viscous influence so that it is available to improve the performance; the rising inlet total temperature can decrease both the specific heat ratio and Reynolds number so that it will lead to the compressor performance decline inevitably.
{"title":"Impact investigation of inlet environmental changes on the rated condition performance of a high-pressure compressor","authors":"Q. Wang, Zhourong Zhang, Shuning Xiao, Qingsong Hong","doi":"10.1515/tjj-2022-0022","DOIUrl":"https://doi.org/10.1515/tjj-2022-0022","url":null,"abstract":"Abstract The variations of inlet environment parameters can make significant effects on the compressor performance. This paper aims to investigate the effects of inlet total pressure and total temperature changes on the rated condition performance of a nine-stage HPC. Different cases of total pressure and total temperature boundary conditions at this compressor inlet are studied by 3-D numerical simulations with experimental validations. The numerical results confirm that the variations of inlet total pressure and total temperature make different effects on the rated condition performance of compressor. The overall performance parameters, such as the corrected mass flow and isentropic efficiency, will increase with inlet total pressure increasing and decrease with inlet total temperature increasing by different change rules. The flow similarity is also investigated by comparing the calculated results of critical quantities in different cases. The results indicate that the rising inlet total pressure can increase the Reynolds number and it is beneficial to reduce the viscous influence so that it is available to improve the performance; the rising inlet total temperature can decrease both the specific heat ratio and Reynolds number so that it will lead to the compressor performance decline inevitably.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44795898","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 passive control of jets using vanes as vortex generators is studied by numerical simulation in this paper. The vanes are positioned inside the nozzle near the exit, inclined to the flow with the longitudinal direction of the jet. Two configurations namely, straight vanes (k = 0 mm−1) and curved vanes (k = 0.05 mm−1) are considered. Curvature k is defined as the reciprocal of the radius of the vanes. The blockage due to the presence of the vanes is 0.5%. The total pressure variation along the jet centreline and along the radial distance is determined from nozzle exit at a Mach number of 0.4, 0.6 and 0.8. It is found that the vanes cause faster decay of the jet, both in the near field and far field compared to the base nozzle (plain circular nozzle) and the curved vanes perform better than the straight vanes in promoting the jet mixing. A maximum of 54% reduction in jet potential core length is achieved by the curved vanes and the jet becomes asymmetrical due to the presence of the vanes inside the nozzle, as observed in the radial pressure decay plots and Mach number contours.
{"title":"Control of subsonic jets using vanes as vortex generators","authors":"Balamani Gandhinathan, Thanigaiarasu Subramanian","doi":"10.1515/tjj-2022-0062","DOIUrl":"https://doi.org/10.1515/tjj-2022-0062","url":null,"abstract":"Abstract The passive control of jets using vanes as vortex generators is studied by numerical simulation in this paper. The vanes are positioned inside the nozzle near the exit, inclined to the flow with the longitudinal direction of the jet. Two configurations namely, straight vanes (k = 0 mm−1) and curved vanes (k = 0.05 mm−1) are considered. Curvature k is defined as the reciprocal of the radius of the vanes. The blockage due to the presence of the vanes is 0.5%. The total pressure variation along the jet centreline and along the radial distance is determined from nozzle exit at a Mach number of 0.4, 0.6 and 0.8. It is found that the vanes cause faster decay of the jet, both in the near field and far field compared to the base nozzle (plain circular nozzle) and the curved vanes perform better than the straight vanes in promoting the jet mixing. A maximum of 54% reduction in jet potential core length is achieved by the curved vanes and the jet becomes asymmetrical due to the presence of the vanes inside the nozzle, as observed in the radial pressure decay plots and Mach number contours.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44626541","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 In view of the problem that the vibration of the centrifugal impeller of the compressor exceeds the standard when a micro turbojet engine crosses the first-order critical speed, this research proposes a vibration control technology for the engine rotor system based on the new integral squeeze film damper (NISFD) according to the unique structure and assembly characteristics of the rotor bearing seat of the micro turbojet engine. Through numerical analysis and experimental research, the dynamic characteristics of NISFD are analyzed, and the vibration reduction mechanism of NISFD is revealed. The engine test verification based on NISFD is carried out. The results show that NISFD has good damping characteristics, which can improve the bending stress and strain energy distribution of the rotor. The engine test proves that NISFD can well solve the problem of excessive vibration of the engine when passing through the first-order critical speed, greatly reduce the vibration level within the working speed range, and significantly improve the reliability of the engine during operation. It provides a solid theoretical basis for the design of aeroengine, and provides a reference for the practical engineering application of NISFD in aeroengine.
{"title":"Research on new integral squeeze film damper vibration control of micro turbojet engine at high speed","authors":"Wenhao Wang, Lidong He, Yangliu Sun, Zijian Wang, Hua-Liang D. Zhang, Qiaoqiao Bao, Xingyun Jia, Hua-jun Dong","doi":"10.1515/tjj-2022-0032","DOIUrl":"https://doi.org/10.1515/tjj-2022-0032","url":null,"abstract":"Abstract In view of the problem that the vibration of the centrifugal impeller of the compressor exceeds the standard when a micro turbojet engine crosses the first-order critical speed, this research proposes a vibration control technology for the engine rotor system based on the new integral squeeze film damper (NISFD) according to the unique structure and assembly characteristics of the rotor bearing seat of the micro turbojet engine. Through numerical analysis and experimental research, the dynamic characteristics of NISFD are analyzed, and the vibration reduction mechanism of NISFD is revealed. The engine test verification based on NISFD is carried out. The results show that NISFD has good damping characteristics, which can improve the bending stress and strain energy distribution of the rotor. The engine test proves that NISFD can well solve the problem of excessive vibration of the engine when passing through the first-order critical speed, greatly reduce the vibration level within the working speed range, and significantly improve the reliability of the engine during operation. It provides a solid theoretical basis for the design of aeroengine, and provides a reference for the practical engineering application of NISFD in aeroengine.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47541151","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}
Le Zhang, Lidong He, Xiaodong Wang, Xinwei Huang, Xingyun Jia, Chunrui Liu
Abstract Aiming at the problems of large leakage and high friction heat generation of the piston ring under high pressure and high speed, based on the previous research on the V-shaped groove piston ring, the research on the design method of the V-shaped groove piston ring is carried out in depth. The numerical analysis is carried out focusing on the number of V-shaped grooves and the depth of the V-shaped grooves of the piston ring. The influence law is verified and analyzed by using a high-pressure and high-speed rotating test bench. The simulation and experimental results show that the leakage of 4 grooves and 8 grooves piston ring is reduced by 14.9 and 28.5%, and the temperature is reduced by 10.9 and 4.7%; When there are 8 V-shaped grooves on the piston ring, the leakage is reduced by 28.5 and 21.7%; when the V-shaped groove depth is 0.04 and 0.08 mm, the temperature is reduced by 4.1%. However, when the V-shaped groove depth is 0.12 mm, the leakage is increased by 2.7% compared with the traditional piston ring. Appropriate groove number and groove depth can realize the coordinated design of low leakage and low friction temperature rise.
{"title":"The design method of the V-shaped groove piston ring","authors":"Le Zhang, Lidong He, Xiaodong Wang, Xinwei Huang, Xingyun Jia, Chunrui Liu","doi":"10.1515/tjj-2022-0033","DOIUrl":"https://doi.org/10.1515/tjj-2022-0033","url":null,"abstract":"Abstract Aiming at the problems of large leakage and high friction heat generation of the piston ring under high pressure and high speed, based on the previous research on the V-shaped groove piston ring, the research on the design method of the V-shaped groove piston ring is carried out in depth. The numerical analysis is carried out focusing on the number of V-shaped grooves and the depth of the V-shaped grooves of the piston ring. The influence law is verified and analyzed by using a high-pressure and high-speed rotating test bench. The simulation and experimental results show that the leakage of 4 grooves and 8 grooves piston ring is reduced by 14.9 and 28.5%, and the temperature is reduced by 10.9 and 4.7%; When there are 8 V-shaped grooves on the piston ring, the leakage is reduced by 28.5 and 21.7%; when the V-shaped groove depth is 0.04 and 0.08 mm, the temperature is reduced by 4.1%. However, when the V-shaped groove depth is 0.12 mm, the leakage is increased by 2.7% compared with the traditional piston ring. Appropriate groove number and groove depth can realize the coordinated design of low leakage and low friction temperature rise.","PeriodicalId":50284,"journal":{"name":"International Journal of Turbo & Jet-Engines","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47995925","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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