A research concerning the coupling conditions of gas leakage through suction valves and capacity regulation is performed in an industrial reciprocating compressor.Both internal flow and thermodynamic characteristic ar...A research concerning the coupling conditions of gas leakage through suction valves and capacity regulation is performed in an industrial reciprocating compressor.Both internal flow and thermodynamic characteristic are discussed in detail.The results show that the capacity of compressor can be regulated steplessly by controlling suction valve closure moment.And then the quantitative relationship between the capacity load and the closing angle of suction valve is revealed.The capacity load and valve leakage rate show obvious different features in P-V diagrams,which makes it easier to define appropriate features for detecting cracked or broken reciprocating compressor valves under varying load conditions.A set of curves of compression work and discharge gas mass are obtained and a method for rating thermal performance of a compressor is presented using these curves.展开更多
Since there always exist interference components which caused by valve vibration,it is hard to directly use cylinder signal for fault diagnosis of reciprocating compressor. Based on Empirical Mode Decomposition (EMD) ...Since there always exist interference components which caused by valve vibration,it is hard to directly use cylinder signal for fault diagnosis of reciprocating compressor. Based on Empirical Mode Decomposition (EMD) coherence,a new method for the fault diagnosis of reciprocating compressor cylinder is presented. Firstly,double channel signals of cylinder and valve are synchronously sampled. Secondly,cyclic cross-correlation function is used to eliminate the time delay between these signals. Finally,EMD coherence method is utilized to remove the interference components from cylinder signal. Thus,more concise and precise working condition information for cylinder and inner components can be obtained. So it is an effective method for fault diagnosis of reciprocating compressor cylinder.展开更多
In the process of capacity regulation of reciprocating compressor, the frequent change of inlet temperature and pressure makes the control of exhaust flow unstable, resulting in the high pressure ratio of the intermed...In the process of capacity regulation of reciprocating compressor, the frequent change of inlet temperature and pressure makes the control of exhaust flow unstable, resulting in the high pressure ratio of the intermediate stage. At last the compressor cannot operate safely. To solve the problem, a novel flow control scheme based on inlet temperature and pressure ratio is proposed. In this scheme, the intake model of the cylinder under the capacity regulation condition is established to calculate the load of the first cylinder. Then, the adaptive predictive PID(APPID) controller is designed to control the pressure ratio of other stages, and the grey prediction model is used to predict the pressure output to overcome the system delay. To solve the problem of control parameters tuning, an improved particle swarm optimization(PSO) algorithm is adopted to obtain the optimal control parameters.The effectiveness of the adaptive predictive PID control method is verified by a two-stage compressor model simulation.Finally, the flow control scheme is applied to the actual four-stage air reciprocating compressor flow control system. Although the temperature difference is greater than 15 ℃, the compressor exhaust flow is maintained at the set value and the pressure ratio is also maintained stable. At the same time, the compressor pressure ratio can be quickly adjusted without overshoot. The application result further verifies the feasibility and effectiveness of the scheme.展开更多
The cooling system,as an important part of high-pressure compressor,has always been a key technical bottleneck for its miniaturization. A new type self-air-cooling system is first proposed for the reciprocating compre...The cooling system,as an important part of high-pressure compressor,has always been a key technical bottleneck for its miniaturization. A new type self-air-cooling system is first proposed for the reciprocating compressor through ingenious structural design without any auxiliary equipment. The transient model of cooling system is established,which regards the cooling passage as a chamber with compressibility and heat exchange considering the linear and local flow resistance. The design principle is achieved by studying the working process and key parameters characteristics,which provides the theoretical foundation for the structural design. The experimental results show that the self-air-cooling system can quickly lower the temperature of the cylinder compared with natural cooling,which has considerable theoretical significance and practical value for the miniature high pressure compressor.展开更多
The aim of this current work is to investigate the effects of operating parameters on heat transfer characteristics between gas and in-cylinder solid surfaces in a reciprocating compressor.A numerical model has been i...The aim of this current work is to investigate the effects of operating parameters on heat transfer characteristics between gas and in-cylinder solid surfaces in a reciprocating compressor.A numerical model has been implemented in MATLAB based on mass balance,the first law of thermodynamics,and NIST REFPROP database for gas properties and thermodynamic relationships.The impacts of key parameters such as rotational speed,suction temperature,pressure ratio and suction pressure are particularly evaluated on heat transfer coefficient(HTC),heat flux(HF)and gas temperature.Results demonstrate that HTC increases markedly with the increase of rotational speed,pressure ratio and suction pressure,and decreases slightly with the increase of suction temperature;the instantaneous HF strengthens significantly with the increase of rotational speed,pressure ratio and suction pressure,whereas the mean HF magnitude transferred from gas to the wall decreases with the increase of rotational speed;the maximum gas temperature is more sensitive to suction temperature and pressure ratio.展开更多
The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequa...The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequate management strategies for these systems in order to improve their availability and productivity to meet those more demanding criteria.In this context,the complex of RAM factors constitute a strategic approach for integrating reliability,availability and maintainability,by using methods,tools and engineering techniques(Mean Time to Failure,Equipment down Time and System Availability values)to identify and quantify equipment and system failures that prevent the achievement of the productive objectives.The application of such methodologies requires a deep experience and know-how together with the possibility of acquiring and processing data in operating conditions.This paper presents the most relevant aspects and findings of a study conducted for assessing the operational performance of a reciprocating compressor system package installed and used in the oil and gas'industries.The study was based on the analysis of the behaviour of states defined for each individual parts and component of reciprocating compressor and also aimed to identify and evaluate the effects of RAMtype factors and was conducted in collaboration with a private company that,for privacy reasons,will be named RC company.The Methodologies procedures used in this descriptive study were the bibliographical research,documentary and content analysis of the main literature.Adopting the most suitable maintenance strategy is one of the main challenges that maintenance managers face.The main purpose of this work is to propose a new approach to evaluate maintenance strategies.In this study,three criteria called reliability,availability and maintainability(RAM)have been employed to compare to future maintenance strategies.展开更多
This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles a...This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles are analyzed synchronously using FLUENT software, and the effects of fluid-structure interaction on the performance of the labyrinth seal are revealed. The results indicate that with the growth of tooth profile angle, the leakage rate of labyrinth seal tends to decrease first, and then increase. The results of fluid-structure interaction analysis are close to those of actual engineering. The effect of fluid-structure interaction makes tiny deformation in calculation mesh of piston and cylinder structure, and the coupling interaction affects the performance of the labyrinth seal.展开更多
基金the National Natural Science Foundation of China(No.52101343)State Key Laboratory of Compressor Technology(An Hui Laboratory of Compressor Technology)(No.SKL-YSJ201808/SKL-YSJ201911)。
文摘A research concerning the coupling conditions of gas leakage through suction valves and capacity regulation is performed in an industrial reciprocating compressor.Both internal flow and thermodynamic characteristic are discussed in detail.The results show that the capacity of compressor can be regulated steplessly by controlling suction valve closure moment.And then the quantitative relationship between the capacity load and the closing angle of suction valve is revealed.The capacity load and valve leakage rate show obvious different features in P-V diagrams,which makes it easier to define appropriate features for detecting cracked or broken reciprocating compressor valves under varying load conditions.A set of curves of compression work and discharge gas mass are obtained and a method for rating thermal performance of a compressor is presented using these curves.
基金Sponsored by the National Natural Science Foundation of China (Grant No.50805014)Key Research Program of Chinese Ministry of Education (Grant No.109047)
文摘Since there always exist interference components which caused by valve vibration,it is hard to directly use cylinder signal for fault diagnosis of reciprocating compressor. Based on Empirical Mode Decomposition (EMD) coherence,a new method for the fault diagnosis of reciprocating compressor cylinder is presented. Firstly,double channel signals of cylinder and valve are synchronously sampled. Secondly,cyclic cross-correlation function is used to eliminate the time delay between these signals. Finally,EMD coherence method is utilized to remove the interference components from cylinder signal. Thus,more concise and precise working condition information for cylinder and inner components can be obtained. So it is an effective method for fault diagnosis of reciprocating compressor cylinder.
基金Supported by the State Key Laboratory of Compressor Technology Open Fund Project(No.SKLYSJ201808/SKLYS201811)the National Key Research and Development Plan(No.2016YFF0203305).
文摘In the process of capacity regulation of reciprocating compressor, the frequent change of inlet temperature and pressure makes the control of exhaust flow unstable, resulting in the high pressure ratio of the intermediate stage. At last the compressor cannot operate safely. To solve the problem, a novel flow control scheme based on inlet temperature and pressure ratio is proposed. In this scheme, the intake model of the cylinder under the capacity regulation condition is established to calculate the load of the first cylinder. Then, the adaptive predictive PID(APPID) controller is designed to control the pressure ratio of other stages, and the grey prediction model is used to predict the pressure output to overcome the system delay. To solve the problem of control parameters tuning, an improved particle swarm optimization(PSO) algorithm is adopted to obtain the optimal control parameters.The effectiveness of the adaptive predictive PID control method is verified by a two-stage compressor model simulation.Finally, the flow control scheme is applied to the actual four-stage air reciprocating compressor flow control system. Although the temperature difference is greater than 15 ℃, the compressor exhaust flow is maintained at the set value and the pressure ratio is also maintained stable. At the same time, the compressor pressure ratio can be quickly adjusted without overshoot. The application result further verifies the feasibility and effectiveness of the scheme.
基金This work was supported by the China Postdoctoral Science Foundation(Grant No.2018M631299)the National Natural Science Foundation of China(Grant No.11872006)。
文摘The cooling system,as an important part of high-pressure compressor,has always been a key technical bottleneck for its miniaturization. A new type self-air-cooling system is first proposed for the reciprocating compressor through ingenious structural design without any auxiliary equipment. The transient model of cooling system is established,which regards the cooling passage as a chamber with compressibility and heat exchange considering the linear and local flow resistance. The design principle is achieved by studying the working process and key parameters characteristics,which provides the theoretical foundation for the structural design. The experimental results show that the self-air-cooling system can quickly lower the temperature of the cylinder compared with natural cooling,which has considerable theoretical significance and practical value for the miniature high pressure compressor.
基金supported by the Research Funds for Young Stars in Science and Technology of Shaanxi Province (2019KJXX-098)China Post-Doctoral Science Foundation Funded Project (2018M640986)+1 种基金the Fundamental Research Funds for Central Universities (xtr042019019)the support of K.C. Wong Education Foundation
文摘The aim of this current work is to investigate the effects of operating parameters on heat transfer characteristics between gas and in-cylinder solid surfaces in a reciprocating compressor.A numerical model has been implemented in MATLAB based on mass balance,the first law of thermodynamics,and NIST REFPROP database for gas properties and thermodynamic relationships.The impacts of key parameters such as rotational speed,suction temperature,pressure ratio and suction pressure are particularly evaluated on heat transfer coefficient(HTC),heat flux(HF)and gas temperature.Results demonstrate that HTC increases markedly with the increase of rotational speed,pressure ratio and suction pressure,and decreases slightly with the increase of suction temperature;the instantaneous HF strengthens significantly with the increase of rotational speed,pressure ratio and suction pressure,whereas the mean HF magnitude transferred from gas to the wall decreases with the increase of rotational speed;the maximum gas temperature is more sensitive to suction temperature and pressure ratio.
文摘The Oil&Gas industry has continuously increased its requirements and together with the high complexity of technological systems and the higher competitiveness of markets,has compelled providers to implement adequate management strategies for these systems in order to improve their availability and productivity to meet those more demanding criteria.In this context,the complex of RAM factors constitute a strategic approach for integrating reliability,availability and maintainability,by using methods,tools and engineering techniques(Mean Time to Failure,Equipment down Time and System Availability values)to identify and quantify equipment and system failures that prevent the achievement of the productive objectives.The application of such methodologies requires a deep experience and know-how together with the possibility of acquiring and processing data in operating conditions.This paper presents the most relevant aspects and findings of a study conducted for assessing the operational performance of a reciprocating compressor system package installed and used in the oil and gas'industries.The study was based on the analysis of the behaviour of states defined for each individual parts and component of reciprocating compressor and also aimed to identify and evaluate the effects of RAMtype factors and was conducted in collaboration with a private company that,for privacy reasons,will be named RC company.The Methodologies procedures used in this descriptive study were the bibliographical research,documentary and content analysis of the main literature.Adopting the most suitable maintenance strategy is one of the main challenges that maintenance managers face.The main purpose of this work is to propose a new approach to evaluate maintenance strategies.In this study,three criteria called reliability,availability and maintainability(RAM)have been employed to compare to future maintenance strategies.
基金the Science and Technology Projects of Liaoning Province(No.2012219020)the China Postdoctoral Science Foundation(No.2013M541249)
文摘This paper addresses the issue of reciprocating compressors staggered labyrinth seal structure. The internal flow field of sealed structure, the displacement of cylinder and piston for different tooth profile angles are analyzed synchronously using FLUENT software, and the effects of fluid-structure interaction on the performance of the labyrinth seal are revealed. The results indicate that with the growth of tooth profile angle, the leakage rate of labyrinth seal tends to decrease first, and then increase. The results of fluid-structure interaction analysis are close to those of actual engineering. The effect of fluid-structure interaction makes tiny deformation in calculation mesh of piston and cylinder structure, and the coupling interaction affects the performance of the labyrinth seal.
