The unbalanced barrel pitching system is a typical electro-hydraulic coupling servo control system, the performance of which determines the response speed and hit probability of vehicle mounted weapon equipment. However, in the actual service process, its core component, the high precision jet pipe servo valve, will produce the gradual erosion of the pilot stage’s receivers and the power stage’s throttling edges, which will induce the performance degradation of the unbalanced barrel pitching system, and finally greatly reduce the performance of barrel weapons. Therefore, a pressure and position double loop state space model of unbalanced barrel pitching system including the core parameters of performance degradation is established. The erosion behavior mechanism model of jet pipe servo valve is constructed, and the performance degradation characteristics of the unbalanced barrel pitching control system under the condition of erosion are further analyzed. Finally, aiming at the double loop structure of internal pressure loop and external position loop, the RBF Network Adaptive Robust Sliding Mode-Proportional Integral Derivative two-stage controller of barrel system is designed, based on which the experimental platform of unbalanced barrel pitching control is built. The experimental results are in good agreement with the theoretical results, so the proposed control method can effectively suppress the degradation of internal structural parameters induced by erosion, that is, it can better compensate the performance degradation of barrel pitching system induced by gradual erosion behavior.
{"title":"The investigation of a unbalanced barrel pitching system’s characteristics degradation and compensation under gradual erosion behavior","authors":"Yuanbo Chu, Yunxia Xia","doi":"10.5755/j02.mech.31873","DOIUrl":"https://doi.org/10.5755/j02.mech.31873","url":null,"abstract":"The unbalanced barrel pitching system is a typical electro-hydraulic coupling servo control system, the performance of which determines the response speed and hit probability of vehicle mounted weapon equipment. However, in the actual service process, its core component, the high precision jet pipe servo valve, will produce the gradual erosion of the pilot stage’s receivers and the power stage’s throttling edges, which will induce the performance degradation of the unbalanced barrel pitching system, and finally greatly reduce the performance of barrel weapons. Therefore, a pressure and position double loop state space model of unbalanced barrel pitching system including the core parameters of performance degradation is established. The erosion behavior mechanism model of jet pipe servo valve is constructed, and the performance degradation characteristics of the unbalanced barrel pitching control system under the condition of erosion are further analyzed. Finally, aiming at the double loop structure of internal pressure loop and external position loop, the RBF Network Adaptive Robust Sliding Mode-Proportional Integral Derivative two-stage controller of barrel system is designed, based on which the experimental platform of unbalanced barrel pitching control is built. The experimental results are in good agreement with the theoretical results, so the proposed control method can effectively suppress the degradation of internal structural parameters induced by erosion, that is, it can better compensate the performance degradation of barrel pitching system induced by gradual erosion behavior. ","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43689382","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}
In this paper, the application requirement of the Residual Property Model based on the decrescent exponential function is reduced to only one mechanical test data. For this, by using Creager and Paris's elastic stress field equation in front of the blunt elliptical hole, the theoretical radius was chosen for the tip curvative and the maximum stress in the load direction at the tip is ensured to be equal the fracture toughness. Thus, the workload of the model is reduced by making the u exponent in the e-u function dependent on the geometric correction factor and the crack length. It was applied to the laminated composite specimens with three-point bending and the specimens including circular hole, and critical fracture stress values close to actual values were achieved.
{"title":"Modified Residual Property Model For Fracture Mechanics","authors":"Goksel Saracoglu","doi":"10.5755/j02.mech.31339","DOIUrl":"https://doi.org/10.5755/j02.mech.31339","url":null,"abstract":"In this paper, the application requirement of the Residual Property Model based on the decrescent exponential function is reduced to only one mechanical test data. For this, by using Creager and Paris's elastic stress field equation in front of the blunt elliptical hole, the theoretical radius was chosen for the tip curvative and the maximum stress in the load direction at the tip is ensured to be equal the fracture toughness. Thus, the workload of the model is reduced by making the u exponent in the e-u function dependent on the geometric correction factor and the crack length. It was applied to the laminated composite specimens with three-point bending and the specimens including circular hole, and critical fracture stress values close to actual values were achieved.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49434107","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}
The matting of gears can be considered one of the most complicated faults to diagnose because its vibratory signature is not really known. In addition, the integration of cracks in digital models is not a simple task. On the other hand, the diagnosis of gears can be done in the time domain through statistical method or in the frequency domain through spectral analysis. In this study we made a vibratory analysis on the whole transmission system from raw mill to the Hamma bouzien-constantine cement plant, and then we compared these results with a numerical model. The numerical results found are very close to the experimental one. The experimental study was carried out by the OMNITREND processing software and the numerical simulation by ansys workbench.
{"title":"Experimental and Numerical Analysis of Helical Gear of Raw Mill in Hamma Bouzian Cement","authors":"Leila Khammar, R. Zellagui","doi":"10.5755/j02.mech.30833","DOIUrl":"https://doi.org/10.5755/j02.mech.30833","url":null,"abstract":"The matting of gears can be considered one of the most complicated faults to diagnose because its vibratory signature is not really known. In addition, the integration of cracks in digital models is not a simple task. On the other hand, the diagnosis of gears can be done in the time domain through statistical method or in the frequency domain through spectral analysis. In this study we made a vibratory analysis on the whole transmission system from raw mill to the Hamma bouzien-constantine cement plant, and then we compared these results with a numerical model. The numerical results found are very close to the experimental one. The experimental study was carried out by the OMNITREND processing software and the numerical simulation by ansys workbench.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41445944","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}
The current research work on the effect of exhaust gas recirculation on the diesel engine for the analysis of performance and emission characteristics with corn oil methyl ester blends. The engine was tested with three fuels are 100diesel, 20B (20%COME + 80% Diesel) and 40B (40%COME + 60% Diesel) with EGR condition of 0% and 20% rate. The engine was evaluated with performance characteristics such as thermal efficiency, brake specific fuel consumption, exhaust gas temperature and emissions such as carbon dioxide, hydrocarbon and oxides of nitrogen. The analysed results of the brake thermal efficiency was reduced with increased brake specific consumption and the exhaust emissions are decreased with increase of biodiesel blend and increased EGR rate.
{"title":"Effect of Corn Oil Methyl Ester and Exhaust Gas Recirculation on Per-formance and Emission Characteristics of Diesel Engine","authors":"Gopinath Varudharajan, Periyasamy R","doi":"10.5755/j02.mech.30805","DOIUrl":"https://doi.org/10.5755/j02.mech.30805","url":null,"abstract":"The current research work on the effect of exhaust gas recirculation on the diesel engine for the analysis of performance and emission characteristics with corn oil methyl ester blends. The engine was tested with three fuels are 100diesel, 20B (20%COME + 80% Diesel) and 40B (40%COME + 60% Diesel) with EGR condition of 0% and 20% rate. The engine was evaluated with performance characteristics such as thermal efficiency, brake specific fuel consumption, exhaust gas temperature and emissions such as carbon dioxide, hydrocarbon and oxides of nitrogen. The analysed results of the brake thermal efficiency was reduced with increased brake specific consumption and the exhaust emissions are decreased with increase of biodiesel blend and increased EGR rate.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49385394","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}
As a key component of the drilling mud pump, the plunger seal often has problems such as seal failure in reconstruction of low-permeability sandstone reservoirs and the development of unconventional reservoirs, which, in turn, leads to low efficiency of drilling mud pumps and even great potential safety hazard. Based on this, this paper designs a three-stage sealing device at the hydraulic head for the 7000 fracturing plunger pump, and analyzes the sealing performance of the system. The effects of different working loads of the hydraulic head and axial pre-tightening force on the contact force of the seal ring and the stress distribution in the seal ring are explored, and the sealing effect of the three-stage seal of the fracturing plunger pump is confirmed. The results show that the peak stress and the peak contact pressure of the three rubber rings increases with the increasing of the working load of the hydraulic head; the peak stress and the peak contact stress of the three rubber rings during the installation process increase with the increase of the installation pre-tightening force. But the equivalent stress peak and the contact stress peak are directly related the fluid load under the action of the working fluid load; the maximum contact force of the rubber during the sealing process of the system is greater than that of the system working medium under different working fluid pressures. With internal pressure, the three sealing rubber rings can play a sealing role to varying degrees in sequence, and increasing the total life of the sealing body.
{"title":"Design of three-stage sealing structure and investigation of sealing performance for 7000 fracturing plunger pump","authors":"Mingjun Du, Jianqiu Xi, Youping Liu, Yongjun Hou, Huachuan Li, Xiaopeng Yang, Zhixi Wang, Qiping Dai, Ping Duan, Mingjian Zhao, Shikai Jiang","doi":"10.5755/j02.mech.31091","DOIUrl":"https://doi.org/10.5755/j02.mech.31091","url":null,"abstract":"As a key component of the drilling mud pump, the plunger seal often has problems such as seal failure in reconstruction of low-permeability sandstone reservoirs and the development of unconventional reservoirs, which, in turn, leads to low efficiency of drilling mud pumps and even great potential safety hazard. Based on this, this paper designs a three-stage sealing device at the hydraulic head for the 7000 fracturing plunger pump, and analyzes the sealing performance of the system. The effects of different working loads of the hydraulic head and axial pre-tightening force on the contact force of the seal ring and the stress distribution in the seal ring are explored, and the sealing effect of the three-stage seal of the fracturing plunger pump is confirmed. The results show that the peak stress and the peak contact pressure of the three rubber rings increases with the increasing of the working load of the hydraulic head; the peak stress and the peak contact stress of the three rubber rings during the installation process increase with the increase of the installation pre-tightening force. But the equivalent stress peak and the contact stress peak are directly related the fluid load under the action of the working fluid load; the maximum contact force of the rubber during the sealing process of the system is greater than that of the system working medium under different working fluid pressures. With internal pressure, the three sealing rubber rings can play a sealing role to varying degrees in sequence, and increasing the total life of the sealing body.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45568027","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}
In the hydrodynamic inclined fixed pad thrust bearing, when the surface separation is ultra low, there will be the special hydrodynamic mode where in the inlet zone occur both the adsorbed boundary layer flows and the intermediate continuum fluid flow i.e. the multiscale flow and in the outlet zone only occurs the physical adsorbed boundary layer flow. This new mode of hydrodynamic bearing has not been addressed before. Here, we present the corresponding multiscale hydrodynamic analysis for this bearing. The inlet zone flow is described by the closed-form explicit multiscale flow equations. The outlet zone flow is described by the nanoscale flow equation. First, the analytical derivations for the pressure distribution and carried load of the bearing were feasibly made by making a reasonable assumption. Then, full numerical solutions to the bearing were obtained to verify the analytical solution. It was found that there are significant differences between the analytically calculated pressure distribution and the numerically solved pressure distribution for the same operating condition; however for the studied different fluid-bearing surface interactions, when the surface separation is relatively large, the analytically derived load equation can be used to calculate the carried load of the bearing. Numerical solutions clearly show that stronger the fluid-bearing surface interaction, higher the generated hydrodynamic pressure in the bearing, and larger the carried load of the bearing. The study not only provides the mathematical tools for studying the bearing but also gives the indication of the strong adsorbed boundary layer effect in this bearing.
{"title":"Multiscale analysis and numerical simulation of hydrodynamic inclined fixed pad thrust bearing with ultra low surface separation","authors":"Wei Zhu, Chen Huang, Chao-Min Wang, Yongbin Zhang","doi":"10.5755/j02.mech.30821","DOIUrl":"https://doi.org/10.5755/j02.mech.30821","url":null,"abstract":"In the hydrodynamic inclined fixed pad thrust bearing, when the surface separation is ultra low, there will be the special hydrodynamic mode where in the inlet zone occur both the adsorbed boundary layer flows and the intermediate continuum fluid flow i.e. the multiscale flow and in the outlet zone only occurs the physical adsorbed boundary layer flow. This new mode of hydrodynamic bearing has not been addressed before. Here, we present the corresponding multiscale hydrodynamic analysis for this bearing. The inlet zone flow is described by the closed-form explicit multiscale flow equations. The outlet zone flow is described by the nanoscale flow equation. First, the analytical derivations for the pressure distribution and carried load of the bearing were feasibly made by making a reasonable assumption. Then, full numerical solutions to the bearing were obtained to verify the analytical solution. It was found that there are significant differences between the analytically calculated pressure distribution and the numerically solved pressure distribution for the same operating condition; however for the studied different fluid-bearing surface interactions, when the surface separation is relatively large, the analytically derived load equation can be used to calculate the carried load of the bearing. Numerical solutions clearly show that stronger the fluid-bearing surface interaction, higher the generated hydrodynamic pressure in the bearing, and larger the carried load of the bearing. The study not only provides the mathematical tools for studying the bearing but also gives the indication of the strong adsorbed boundary layer effect in this bearing.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47634770","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}
In many engineering applications, particle-laden flows are a necessary part of the conveying process, but in other situations, they could have unintended consequences that must be avoided. As a part of the exhausting process, the induced cement-mill fan (FN-280) installed in a cement plant operates under critical conditions with the presence of high content of cement particles. Over time the dragged solid particles erode the rotating and stationary parts of the fan causing their damage. If one decides on a numerical approach to predict regions most prone to erosion and track the solid particle's trajectory within the fan domain by assuming a one-way coupling regime between the continuous and discrete solid phases, a deep insight into the flows physics within the centrifugal fan is required. With this aim, a three-dimensional numerical approach for the hole unsteady flow in a large-sized industrial centrifugal fan has been carried out in this paper. A fully resolved sliding mesh approach was employed to take into account the unsteady interaction between the impeller and the discharge volute. Based on the characteristic performance curves, the numerical results of the unsteady simulation at four operating conditions are validated with the experimental data. The comparisons reveal that the results of the unsteady simulation are in an acceptable level of agreement with the experiment, demonstrating the validity of the modelling approach adopted in this study.
{"title":"Transient Numerical Simulation of a Large-Sized Cement-Mill Fan for Performance Prediction","authors":"Aissa Amour, N. Menasri","doi":"10.5755/j02.mech.32170","DOIUrl":"https://doi.org/10.5755/j02.mech.32170","url":null,"abstract":"In many engineering applications, particle-laden flows are a necessary part of the conveying process, but in other situations, they could have unintended consequences that must be avoided. As a part of the exhausting process, the induced cement-mill fan (FN-280) installed in a cement plant operates under critical conditions with the presence of high content of cement particles. Over time the dragged solid particles erode the rotating and stationary parts of the fan causing their damage. If one decides on a numerical approach to predict regions most prone to erosion and track the solid particle's trajectory within the fan domain by assuming a one-way coupling regime between the continuous and discrete solid phases, a deep insight into the flows physics within the centrifugal fan is required. With this aim, a three-dimensional numerical approach for the hole unsteady flow in a large-sized industrial centrifugal fan has been carried out in this paper. A fully resolved sliding mesh approach was employed to take into account the unsteady interaction between the impeller and the discharge volute. Based on the characteristic performance curves, the numerical results of the unsteady simulation at four operating conditions are validated with the experimental data. The comparisons reveal that the results of the unsteady simulation are in an acceptable level of agreement with the experiment, demonstrating the validity of the modelling approach adopted in this study.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47823579","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}
This study proposes a vibration suppression technique that uses piezoelectric material to restrict the dynamic amplitudes of a cantilever beam. The finite element analysis (FEA) model of the cantilever is created and incorporated with Macro Fiber Composite (MFC8507-P2) in the ANSYS framework. A comparative study has been performed using three different types of materials i.e., Polylactic acid (PLA), PLA with Short Carbon Fibers (PLA-SCF Composite), and PLA with Continuous Carbon Fibers (PLA-CCF Composite), for the beam. An external disturbance causes the beam to vibrate, and the MFC8507-P2 patch provides a counter-force to the structure to reduce vibrations. The MFC8507-P2 patch is placed at an appropriate location on each beam to suppress vibration induced by the initial fundamental modes. Modal analysis has been performed to find the natural frequencies and the contribution of each mode to the overall response under dynamic loading conditions. Transient structural analysis is performed to observe the influence of the MFC8507-P2 patch on vibration amplitude with time. Furthermore, frequency response analysis has been performed to determine the impact of the MFC8507-P2 patch on the vibration amplitude of the natural modes. The vibration response has been measured at the tip of the beam and the simulation results validate that the vibration amplitude decreases as the applied voltage increases.
{"title":"Actuation Performance of Macro Fibre Composite (MFC) as Actuator in Vibration Reduction of Cantilever Beams","authors":"R. Rimašauskienė, A. Raza, Swarup Mahato","doi":"10.5755/j02.mech.31732","DOIUrl":"https://doi.org/10.5755/j02.mech.31732","url":null,"abstract":"This study proposes a vibration suppression technique that uses piezoelectric material to restrict the dynamic amplitudes of a cantilever beam. The finite element analysis (FEA) model of the cantilever is created and incorporated with Macro Fiber Composite (MFC8507-P2) in the ANSYS framework. A comparative study has been performed using three different types of materials i.e., Polylactic acid (PLA), PLA with Short Carbon Fibers (PLA-SCF Composite), and PLA with Continuous Carbon Fibers (PLA-CCF Composite), for the beam. An external disturbance causes the beam to vibrate, and the MFC8507-P2 patch provides a counter-force to the structure to reduce vibrations. The MFC8507-P2 patch is placed at an appropriate location on each beam to suppress vibration induced by the initial fundamental modes. Modal analysis has been performed to find the natural frequencies and the contribution of each mode to the overall response under dynamic loading conditions. Transient structural analysis is performed to observe the influence of the MFC8507-P2 patch on vibration amplitude with time. Furthermore, frequency response analysis has been performed to determine the impact of the MFC8507-P2 patch on the vibration amplitude of the natural modes. The vibration response has been measured at the tip of the beam and the simulation results validate that the vibration amplitude decreases as the applied voltage increases.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48364293","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}
Haohao Du, Chenghu Jing, Bingsheng Yan, Chun‐Bin Liu
In this paper, a passive-based adaptive robust super-twisting nonlinear controller (PBARSNC) is proposed for high accuracy torque tracking control of the novel electro-hydraulic loading system with disturbances and uncertainties. The construction of the stability of this electro-hydraulic control system is given using passivity theory that results in a passivity-based controller (PBC). Considering parameter uncertainties and constant or slowly varying disturbances, adaptive law is adopted in the passivity-based controller. Furthermore, super-twisting second-order sliding mode control is used to reject modeling uncertainties and matched disturbances. Passivity theory, adaptive method and super-twisting algorithm are synthesized via the recursive design method. The proposed passive-based adaptive robust super-twisting nonlinear control can guarantee the torque tracking performance in the presence of various uncertainties, which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive simulations are carried out to verify the high-accuracy tracking performance of the proposed control strategy.
{"title":"Passivity-based adaptive robust super-twisting nonlinear control for electro-hydraulic system with uncertainties and disturbances","authors":"Haohao Du, Chenghu Jing, Bingsheng Yan, Chun‐Bin Liu","doi":"10.5755/j02.mech.32405","DOIUrl":"https://doi.org/10.5755/j02.mech.32405","url":null,"abstract":"In this paper, a passive-based adaptive robust super-twisting nonlinear controller (PBARSNC) is proposed for high accuracy torque tracking control of the novel electro-hydraulic loading system with disturbances and uncertainties. The construction of the stability of this electro-hydraulic control system is given using passivity theory that results in a passivity-based controller (PBC). Considering parameter uncertainties and constant or slowly varying disturbances, adaptive law is adopted in the passivity-based controller. Furthermore, super-twisting second-order sliding mode control is used to reject modeling uncertainties and matched disturbances. Passivity theory, adaptive method and super-twisting algorithm are synthesized via the recursive design method. The proposed passive-based adaptive robust super-twisting nonlinear control can guarantee the torque tracking performance in the presence of various uncertainties, which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive simulations are carried out to verify the high-accuracy tracking performance of the proposed control strategy.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49038978","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}
M. Beriache, Brahim Hicham Cherki, L. Mokhtar Saïdia, N. A. Che Sidik, M. Rizalman
In the present work, enhancement of the thermal performance of a central processor unit (CPU) cooling system through a heat sink subjected to an impinging air jet is realized. The height of the impinging air jet duct, the mode of air flow on the heat sink, air blowing mode and as well as the suction blow mode "pull" and the air jet duct geometry are three important influence parameters on the phenomenon. The results obtained show that a jet height H = 20mm, a convergent duct of H = 40mm in height and a hair dryer tip provide further improvement of the cooling technique. The two preceding parameters combined with the fan air suction blow mode improve the performance by at least 11,2% compared to the initial configuration (marketed product), having as characteristics (H = 0mm, fan in the blowing push mode). The use of a converging duct and a hair dryer conduit show that the velocities from the hair dryer tip far exceed those from the best standard conduit height, H=20 mm. That said, the improvement of the flow in the central zone is substantially achieved, which consequently improves the heat removal in this zone at least 19%.
{"title":"Heat Transfer Enhancement through Different Heat Sink/Impinging Air Jet Parameters an Experimental Approach","authors":"M. Beriache, Brahim Hicham Cherki, L. Mokhtar Saïdia, N. A. Che Sidik, M. Rizalman","doi":"10.5755/j02.mech.31929","DOIUrl":"https://doi.org/10.5755/j02.mech.31929","url":null,"abstract":"In the present work, enhancement of the thermal performance of a central processor unit (CPU) cooling system through a heat sink subjected to an impinging air jet is realized. The height of the impinging air jet duct, the mode of air flow on the heat sink, air blowing mode and as well as the suction blow mode \"pull\" and the air jet duct geometry are three important influence parameters on the phenomenon. The results obtained show that a jet height H = 20mm, a convergent duct of H = 40mm in height and a hair dryer tip provide further improvement of the cooling technique. The two preceding parameters combined with the fan air suction blow mode improve the performance by at least 11,2% compared to the initial configuration (marketed product), having as characteristics (H = 0mm, fan in the blowing push mode). The use of a converging duct and a hair dryer conduit show that the velocities from the hair dryer tip far exceed those from the best standard conduit height, H=20 mm. That said, the improvement of the flow in the central zone is substantially achieved, which consequently improves the heat removal in this zone at least 19%.","PeriodicalId":54741,"journal":{"name":"Mechanika","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41869277","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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