Pub Date : 2023-11-07DOI: 10.13052/ijfp1439-9776.2442
Zhiwen Wang, Bo Yang, Qian Ma, Hu Wang, Rupp Carriveau, David S-K. Ting, Wei Xiong
Pneumatic systems are widely used in industrial production sectors. Increasing penetrations of Intelligent Manufacturing and Green Manufacturing are highlighting the drawbacks of pneumatic technology in terms of particularly low energy efficiency and low-level fault diagnosis intelligence. Here we propose that a combined energy-based maintenance and fault diagnostic approach for pneumatic systems could be a game-changer for pneumatics. In this study, a pneumatic cylinder with internal and external leakages is examined and a typical pneumatic experimental system is built. Exergy is adopted for evaluating the available energy of compressed air. Data-driven machine learning models, SAE + SoftMax neural network model and SAE + SVM model, are developed for fault detection and diagnosis. By comparing different machine learning methods with various pressure, flowrate, and exergy data, it is found that the diagnostic accuracy when using pressure and flowrate data is highly dependent on operating conditions, while the diagnostic accuracy when using exergy data is always high regardless of operating conditions. This indicates the promise of developing an exergy-based maintenance paradigm in pneumatic systems. Besides, with exergy and machine learning, more downstream faults can be detected and diagnosed with fewer upstream sensors. This study is the first attempt to develop an exergy-based maintenance paradigm in pneumatic systems. We hope it could inspire the following investigations in other energy domains.
{"title":"Facilitating Energy Monitoring and Fault Diagnosis of Pneumatic Cylinders with Exergy and Machine Learning","authors":"Zhiwen Wang, Bo Yang, Qian Ma, Hu Wang, Rupp Carriveau, David S-K. Ting, Wei Xiong","doi":"10.13052/ijfp1439-9776.2442","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2442","url":null,"abstract":"Pneumatic systems are widely used in industrial production sectors. Increasing penetrations of Intelligent Manufacturing and Green Manufacturing are highlighting the drawbacks of pneumatic technology in terms of particularly low energy efficiency and low-level fault diagnosis intelligence. Here we propose that a combined energy-based maintenance and fault diagnostic approach for pneumatic systems could be a game-changer for pneumatics. In this study, a pneumatic cylinder with internal and external leakages is examined and a typical pneumatic experimental system is built. Exergy is adopted for evaluating the available energy of compressed air. Data-driven machine learning models, SAE + SoftMax neural network model and SAE + SVM model, are developed for fault detection and diagnosis. By comparing different machine learning methods with various pressure, flowrate, and exergy data, it is found that the diagnostic accuracy when using pressure and flowrate data is highly dependent on operating conditions, while the diagnostic accuracy when using exergy data is always high regardless of operating conditions. This indicates the promise of developing an exergy-based maintenance paradigm in pneumatic systems. Besides, with exergy and machine learning, more downstream faults can be detected and diagnosed with fewer upstream sensors. This study is the first attempt to develop an exergy-based maintenance paradigm in pneumatic systems. We hope it could inspire the following investigations in other energy domains.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":"28 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135540049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-07DOI: 10.13052/ijfp1439-9776.2441
El Mehdi El Bahloul, Hicham Aissaoui, Mohammed Diany, Elhassan Boudaia, Mustapha Mabrouki
In industrial facilities, leaks from manufacturing equipment represent uncontrolled fugitive emissions. The most critical components in this equipment are the seals. Several types of seals are used and the most popular are flat seals and O-rings. These seals are subject to high clamping loads and pressures. The failure of the seals could seriously affect the safety of people, and also the environment by the leakage of toxic products. In this work, the analysis of the mechanical and leakage behavior of the O-ring seal reinforced by a metal core and a conventional one when placed either between two plates or in a rectangular groove is presented. Four finite element models, developed using Ansys software, are used to study the behavior of the assemblies in the four cases when clamping load and fluid pressure are applied. This study shows that the introduction of a metal core inside an elastomer O-ring improves the sealing in pressurized installations. The comparison between the assembly without and with a groove shows that the installation of the two studied seals in a groove can protect them against the high stresses which can cause their deterioration and thus increase the probability of failure.
{"title":"Performance Analysis of a Pressurized Assembly with a Reinforced O-ring","authors":"El Mehdi El Bahloul, Hicham Aissaoui, Mohammed Diany, Elhassan Boudaia, Mustapha Mabrouki","doi":"10.13052/ijfp1439-9776.2441","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2441","url":null,"abstract":"In industrial facilities, leaks from manufacturing equipment represent uncontrolled fugitive emissions. The most critical components in this equipment are the seals. Several types of seals are used and the most popular are flat seals and O-rings. These seals are subject to high clamping loads and pressures. The failure of the seals could seriously affect the safety of people, and also the environment by the leakage of toxic products. In this work, the analysis of the mechanical and leakage behavior of the O-ring seal reinforced by a metal core and a conventional one when placed either between two plates or in a rectangular groove is presented. Four finite element models, developed using Ansys software, are used to study the behavior of the assemblies in the four cases when clamping load and fluid pressure are applied. This study shows that the introduction of a metal core inside an elastomer O-ring improves the sealing in pressurized installations. The comparison between the assembly without and with a groove shows that the installation of the two studied seals in a groove can protect them against the high stresses which can cause their deterioration and thus increase the probability of failure.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":"30 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135540200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-07DOI: 10.13052/ijfp1439-9776.2443
Essam Elsaed, Matti Linjama
Hydraulic systems have been widely used due to their high power-to-weight ratio. Despite the growing instances of being superseded by the electromechanical counterparts at low power levels, the market was incapable of presenting alternatives for large-size applications. Additionally, in recent years, the demand for more significant heavy machinery (Mobile & Industrial) has increased, which led to the necessity of even higher flow and pressure Pilot-operated valves, despite the fact that these valves have several issues. One might think the alternative could be developing a hydraulic system that does not rely on Pilot-operated valves, but after decades of research, these systems could not get close to the performance of Pilot-operated Multistage valves. The paper presents a comprehensive study of the progress accomplished from the year 2016 to early 2022 in hydraulic Pilot-operated valves; they are widely employed among ordinary valves, proportional valves, and state-of-the-art digital hydraulics. Higher efficiency will be a primary factor in the success of the new designs. The academia presented several studies to improve the Pilot valves’ performance, but still, they are limited. There are no dramatic developments, and there are only a few upgrades.
{"title":"A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study","authors":"Essam Elsaed, Matti Linjama","doi":"10.13052/ijfp1439-9776.2443","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2443","url":null,"abstract":"Hydraulic systems have been widely used due to their high power-to-weight ratio. Despite the growing instances of being superseded by the electromechanical counterparts at low power levels, the market was incapable of presenting alternatives for large-size applications. Additionally, in recent years, the demand for more significant heavy machinery (Mobile & Industrial) has increased, which led to the necessity of even higher flow and pressure Pilot-operated valves, despite the fact that these valves have several issues. One might think the alternative could be developing a hydraulic system that does not rely on Pilot-operated valves, but after decades of research, these systems could not get close to the performance of Pilot-operated Multistage valves. The paper presents a comprehensive study of the progress accomplished from the year 2016 to early 2022 in hydraulic Pilot-operated valves; they are widely employed among ordinary valves, proportional valves, and state-of-the-art digital hydraulics. Higher efficiency will be a primary factor in the success of the new designs. The academia presented several studies to improve the Pilot valves’ performance, but still, they are limited. There are no dramatic developments, and there are only a few upgrades.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":"29 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135540047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the requirement of the exploitation of marine resources, the execution of specific underwater tasks by onboard manipulators has become one of the key research fields in domestic and all over the world. Based on the underwater capture system designed for the UUV recycling task, which consists of an underwater manipulator and a mechanical capture device, this paper first constructs the kinematics and dynamics model of the capture system through theoretical analysis such as theoretical mechanics and theory of mechanism. Then, combined with the requirements of the recycling task, through the theoretical basis of fluid mechanics such as Morrison equation, dynamic of the capture system in underwater environment is analysed, with a compliant controller designed for the capture system based on impedance theory in order to reduce the impact of underwater environment in the capture task. Moreover, as the capture system modelled in the Adams dynamics simulation platform, it is verified that the designed compliant controller can reduce the underwater environmental impact through simulation experiments in the Adams dynamic platform.
{"title":"Research on Compliant Controller of Underwater Mechanical Capture System Based on Impedance Theory","authors":"Yuanjie Liu, Fu-Yuan Zha, Qiming Wang, Chao Zheng, Jinrui Zhou, Lianzhao Zhang","doi":"10.13052/ijfp1439-9776.2432","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2432","url":null,"abstract":"Due to the requirement of the exploitation of marine resources, the execution of specific underwater tasks by onboard manipulators has become one of the key research fields in domestic and all over the world. Based on the underwater capture system designed for the UUV recycling task, which consists of an underwater manipulator and a mechanical capture device, this paper first constructs the kinematics and dynamics model of the capture system through theoretical analysis such as theoretical mechanics and theory of mechanism. Then, combined with the requirements of the recycling task, through the theoretical basis of fluid mechanics such as Morrison equation, dynamic of the capture system in underwater environment is analysed, with a compliant controller designed for the capture system based on impedance theory in order to reduce the impact of underwater environment in the capture task. Moreover, as the capture system modelled in the Adams dynamics simulation platform, it is verified that the designed compliant controller can reduce the underwater environmental impact through simulation experiments in the Adams dynamic platform.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47345282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.13052/ijfp1439-9776.2433
M. Gong, Cunyuan Ma, Annan He, Wen Huang, Huaijin Yan
Under different working conditions of the aeroengine, the rotating speed of the turbine blades is diverse, and this causes the high-temperature gas mainstream to impact the turbine blades at disparate angles of attack. In order to explore the film cooling mechanism of the pressure surface and suction surface of aeroengine turbine blade at unusual speed, a 3D model of the turbine blades and internal runners is constructed, which refers to Pratt & Whitney PW4084 primary HPT blade. In this model, the high-temperature gas mainstream is set to attack the turbine blades through three distinct angles, the turbine blade air film cooling model is established, and the numerical simulation is conducted at the different blowing ratios. The results showed that the angle of impact (rotational speed) is the key factor affecting the cooling efficiency of the blade. The cooling effect of the suction surface is the best under the positive attack, however, the cooling effect of the pressure surface under the negative attack angle is the first-rate. With the increase of the speed, the surface temperature of the top and tail of the blade pressure surface will gradually decrease, and as the speed reduces, the surface temperature of the lower part of the suction surface of the blade will slightly increase. Finally, under three different attack angles, the cooling efficiency of the air film on the surface of the blade will augment with the increase of the blowing ratio.
{"title":"Effect of Blowing Ratio on Turbine Blade Air Film Cooling Under Different Engine Conditions","authors":"M. Gong, Cunyuan Ma, Annan He, Wen Huang, Huaijin Yan","doi":"10.13052/ijfp1439-9776.2433","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2433","url":null,"abstract":"Under different working conditions of the aeroengine, the rotating speed of the turbine blades is diverse, and this causes the high-temperature gas mainstream to impact the turbine blades at disparate angles of attack. In order to explore the film cooling mechanism of the pressure surface and suction surface of aeroengine turbine blade at unusual speed, a 3D model of the turbine blades and internal runners is constructed, which refers to Pratt & Whitney PW4084 primary HPT blade. In this model, the high-temperature gas mainstream is set to attack the turbine blades through three distinct angles, the turbine blade air film cooling model is established, and the numerical simulation is conducted at the different blowing ratios. The results showed that the angle of impact (rotational speed) is the key factor affecting the cooling efficiency of the blade. The cooling effect of the suction surface is the best under the positive attack, however, the cooling effect of the pressure surface under the negative attack angle is the first-rate. With the increase of the speed, the surface temperature of the top and tail of the blade pressure surface will gradually decrease, and as the speed reduces, the surface temperature of the lower part of the suction surface of the blade will slightly increase. Finally, under three different attack angles, the cooling efficiency of the air film on the surface of the blade will augment with the increase of the blowing ratio.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43016180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.13052/ijfp1439-9776.2431
Xiaolu Hu, Guibing Shi, Yifan Lai, Li Wang, Juntao Yu
High loss density, small volume and difficulty heat dissipation become important factors restricting the development of high-speed motor. In this paper, a new type of high-speed magnetic suspension amorphous motor was studied and its loss and temperature rise were analysed. The influence of cooling fan on air friction loss and cooling effect under different working conditions was studied through fluid analysis. The advantages of magnetic suspension amorphous motor were verified by analysing temperature distribution and efficiency under different conditions. The accuracy of the simulation results was verified by building an experimental platform to test the temperature of the prototype. It is showed that the application of new materials and new technologies is of great significance to improve the efficiency and stability of traditional motors.
{"title":"Loss Calculation and Thermal Analysis of High-speed Magnetic Suspension Amorphous Motor","authors":"Xiaolu Hu, Guibing Shi, Yifan Lai, Li Wang, Juntao Yu","doi":"10.13052/ijfp1439-9776.2431","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2431","url":null,"abstract":"High loss density, small volume and difficulty heat dissipation become important factors restricting the development of high-speed motor. In this paper, a new type of high-speed magnetic suspension amorphous motor was studied and its loss and temperature rise were analysed. The influence of cooling fan on air friction loss and cooling effect under different working conditions was studied through fluid analysis. The advantages of magnetic suspension amorphous motor were verified by analysing temperature distribution and efficiency under different conditions. The accuracy of the simulation results was verified by building an experimental platform to test the temperature of the prototype. It is showed that the application of new materials and new technologies is of great significance to improve the efficiency and stability of traditional motors.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47839004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.13052/ijfp1439-9776.2434
Jie Tang, Z. Zhong, Xin Lu, Liwen Wang
Engine blades will be contaminated during operation, On-line cleaning is the main method to solve blade fouling. In order to study the effect of jet parameters on the flow field of aero-engine cleaning, a low-pressure first-stage rotor flow channel model of a CFM56-7B engine was established, and the changes in the parameter of the cleaning flow field were analyzed under different incident pressures. The results showed that as the jet pressure increased, the average pressure along the blade height increased, whereas the average pressure along the cross section at 50% blade chord length decreased. The vorticity along the blade height cross section increased first and then decreased as the jet pressure increased, whereas the vorticity along the blade chord length cross section remained basically unchanged after the jet pressure reached 3 bar. Comparing experimental results, when the pressure is maintained at 3 bar, better cleaning effect can be obtained. The research provides a theoretical basis for the on-line cleaning.
{"title":"Influence of Jet Parameters on the Aero Engine Cleaning Flow Field","authors":"Jie Tang, Z. Zhong, Xin Lu, Liwen Wang","doi":"10.13052/ijfp1439-9776.2434","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2434","url":null,"abstract":"Engine blades will be contaminated during operation, On-line cleaning is the main method to solve blade fouling. In order to study the effect of jet parameters on the flow field of aero-engine cleaning, a low-pressure first-stage rotor flow channel model of a CFM56-7B engine was established, and the changes in the parameter of the cleaning flow field were analyzed under different incident pressures. The results showed that as the jet pressure increased, the average pressure along the blade height increased, whereas the average pressure along the cross section at 50% blade chord length decreased. The vorticity along the blade height cross section increased first and then decreased as the jet pressure increased, whereas the vorticity along the blade chord length cross section remained basically unchanged after the jet pressure reached 3 bar. Comparing experimental results, when the pressure is maintained at 3 bar, better cleaning effect can be obtained. The research provides a theoretical basis for the on-line cleaning.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47262029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.13052/ijfp1439-9776.2439
Jianbao Yang, Yang Zhang, Duanwei Shi
Shallow water sloshing-structure interaction under the coupled longitudinal and pitch motions resulted by the longitudinal earthquake directly affects the structural safety of the shiplift. However, no matter in shiplift or other related fields, there is little research on this aspect at present. As a basis of structural dynamics analysis and earthquake resistant design, an analytical method including a developed modal system and new engineering formulas is presented to predict the hydrodynamic moment and force in the ship chamber. Based on the linear modal theory, a modal system describing shallow water sloshing under longitudinal earthquake is developed with infinite set of modal functions. Then, new engineering formulas for calculating the hydrodynamic moment and force are proposed with only retaining the lowest sloshing mode (n=1). Case simulations suggest that the maximum error of hydrodynamic moment and force between n=1 and n=100 are lower than 1.3% and 10.5%, respectively. In addition, the hydrodynamic moment resulting from pressure on the walls can be reasonably ignored, which accounts for less than 0.5% percent of total hydrodynamic moment. With respect to the currently used Housner model, the presented formulas are greatly improved in computational accuracy and rationally supplement the missing part in the seismic design part of the Design code for shiplift.
{"title":"Hydrodynamic Analysis of Shallow Water Sloshing in Ship Chamber Under Longitudinal Earthquake","authors":"Jianbao Yang, Yang Zhang, Duanwei Shi","doi":"10.13052/ijfp1439-9776.2439","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2439","url":null,"abstract":"Shallow water sloshing-structure interaction under the coupled longitudinal and pitch motions resulted by the longitudinal earthquake directly affects the structural safety of the shiplift. However, no matter in shiplift or other related fields, there is little research on this aspect at present. As a basis of structural dynamics analysis and earthquake resistant design, an analytical method including a developed modal system and new engineering formulas is presented to predict the hydrodynamic moment and force in the ship chamber. Based on the linear modal theory, a modal system describing shallow water sloshing under longitudinal earthquake is developed with infinite set of modal functions. Then, new engineering formulas for calculating the hydrodynamic moment and force are proposed with only retaining the lowest sloshing mode (n=1). Case simulations suggest that the maximum error of hydrodynamic moment and force between n=1 and n=100 are lower than 1.3% and 10.5%, respectively. In addition, the hydrodynamic moment resulting from pressure on the walls can be reasonably ignored, which accounts for less than 0.5% percent of total hydrodynamic moment. With respect to the currently used Housner model, the presented formulas are greatly improved in computational accuracy and rationally supplement the missing part in the seismic design part of the Design code for shiplift.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42835644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.13052/ijfp1439-9776.2438
Zhao Guochao, Yin Shi, Song Yuning, Wang Hui
The paper proposes a new double-stage large flow protection relief valve based on the double-stage linkage structure, to solve the problem that when it is impacted by the top plate, the traditional hydraulic support protective relief valve has smaller overflow and lower sensitivity, which causes the column circuit to be damaged. The flow field characteristics of double-stage protective relief valve are numerically simulated by the computational fluid dynamics method and semi-implicit connection pressure equation calculation model. Then the dynamic characteristics of the flow field distribution of the double-stage protective relief valve are obtained. According to the law of fluid flow, the structure of main valve core is optimized for the negative pressure, cavitation and vortex area. The flow field characteristics of the optimized double-stage protection valve are simulated and analyzed. In the end, the flow field characteristics of optimized double-stage protective relief valve are compared with the original. The results show that the negative pressure value of double-stage protective relief valve is reduced by 15%, and the outlet velocity of double-stage protective relief valve is reduced by 21% compared to the unoptimized when the main core is fully opened. The research results provide reference for the evolution design of high-flow, impact-resistant hydraulic support safety valve structure.
{"title":"Flow Field Characteristics and Structure Improvement of Double-stage Safety Valve","authors":"Zhao Guochao, Yin Shi, Song Yuning, Wang Hui","doi":"10.13052/ijfp1439-9776.2438","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2438","url":null,"abstract":"The paper proposes a new double-stage large flow protection relief valve based on the double-stage linkage structure, to solve the problem that when it is impacted by the top plate, the traditional hydraulic support protective relief valve has smaller overflow and lower sensitivity, which causes the column circuit to be damaged. The flow field characteristics of double-stage protective relief valve are numerically simulated by the computational fluid dynamics method and semi-implicit connection pressure equation calculation model. Then the dynamic characteristics of the flow field distribution of the double-stage protective relief valve are obtained. According to the law of fluid flow, the structure of main valve core is optimized for the negative pressure, cavitation and vortex area. The flow field characteristics of the optimized double-stage protection valve are simulated and analyzed. In the end, the flow field characteristics of optimized double-stage protective relief valve are compared with the original. The results show that the negative pressure value of double-stage protective relief valve is reduced by 15%, and the outlet velocity of double-stage protective relief valve is reduced by 21% compared to the unoptimized when the main core is fully opened. The research results provide reference for the evolution design of high-flow, impact-resistant hydraulic support safety valve structure.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45925617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hydrodynamic effect is one of the key phenomena in journal bearing lubrication. Many researches have been carried out on the supporting force of journal bearing, the motion of suspension shaft and the lubrication effect. This paper studies the hydrodynamic effect from another point of view, that is, the pumping effect caused by the rotation of the eccentric shaft with fixed axis. The clearance between the rotor and the stator is divided into two sections by the inlet port and the outlet port. Their mathematical models are established and studied in polar coordinates. The pressure distribution and pumping flowrate in the flow field are studied theoretically. Under the conditions analyzed in this paper, an output flow larger than 90 ml/s could be generated, overcoming a load pressure of 0.5 MPa. In addition, the pressure distribution and pumping flowrate of the mechanism are affected by the pumping outlet orientation. According to the analysis results of the output angle range from π/8 to 3π/4, when the pump outlet angle is set near 3π/8 to π/2, the pumping flowrate reaches the maximum value of 91.83 ml/s, and nearly half 48% of the inflow liquid can be pumped out to the outlet.
{"title":"Study of Hydrodnamic Pumping Effects of Fixed Axis Rotation in Eccentric Annular Flow Field","authors":"Tong Guo, T. Luo, Tianliang Lin, Qihuai Chen, Haoling Ren, Yuanhua Yu","doi":"10.13052/ijfp1439-9776.2437","DOIUrl":"https://doi.org/10.13052/ijfp1439-9776.2437","url":null,"abstract":"Hydrodynamic effect is one of the key phenomena in journal bearing lubrication. Many researches have been carried out on the supporting force of journal bearing, the motion of suspension shaft and the lubrication effect. This paper studies the hydrodynamic effect from another point of view, that is, the pumping effect caused by the rotation of the eccentric shaft with fixed axis. The clearance between the rotor and the stator is divided into two sections by the inlet port and the outlet port. Their mathematical models are established and studied in polar coordinates. The pressure distribution and pumping flowrate in the flow field are studied theoretically. Under the conditions analyzed in this paper, an output flow larger than 90 ml/s could be generated, overcoming a load pressure of 0.5 MPa. In addition, the pressure distribution and pumping flowrate of the mechanism are affected by the pumping outlet orientation. According to the analysis results of the output angle range from π/8 to 3π/4, when the pump outlet angle is set near 3π/8 to π/2, the pumping flowrate reaches the maximum value of 91.83 ml/s, and nearly half 48% of the inflow liquid can be pumped out to the outlet.","PeriodicalId":13977,"journal":{"name":"International Journal of Fluid Power","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66116692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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