The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Roberto Cipollone - One of the best experts on this subject based on the ideXlab platform.
-
energy saving potential in existing volumetric Rotary Compressors
Energy Procedia, 2015Co-Authors: Diego Vittorini, Giuseppe Bianchi, Roberto CipolloneAbstract:Abstract The issues of energy and Carbon saving in energy intensive sectors, along with that of energy generation from renewable sources, have been recently receiving a growing awareness, as they are perceived as the most effective ways to deal with global sustainability commitments. The Compressed Air Sector (CAS) accounts for a 10% worldwide electricity consumption, and thus is being re-thought as an area offering great opportunities for improvement. Considering that the compression is responsible for a 10-15% consumption, it is vital to pay attention to machines performances. An overview of present compressor technology is given and saving directions for Screw and Sliding Vanes machines are analyzed: interesting source of information was the Compressed Air and Gas Institute (CAGI), whose data have been processed, in order to obtain consistency with fixed reference pressures, and organized as a function of main operating parameters. The overall efficiency has been split and all different sub-terms (adiabatic, volumetric, mechanical, electrical, organic) considered separately. This has allowed a term-by-term evaluation of the margin for improvement. The heat recovery from the oil into mechanical energy via an Organic Rankine Cycle (ORC), together with the thermodynamic improvement during compression phase opens the way to a step change concerning the specific energy consumption.
-
friction power modeling and measurements in sliding vane Rotary Compressors
Applied Thermal Engineering, 2015Co-Authors: Giuseppe Bianchi, Roberto CipolloneAbstract:The authors acknowledge Ing. Enea Mattei S.p.A. and particularly its CEO, Dr. Giulio Contaldi, for continuous research funding and support. The work has been done also under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” funded by the European Commission.
-
energy saving in sliding vane Rotary Compressors using pressure swirl oil atomizers
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2015Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:The work has been done under the FP7 project ‘‘Complete Vehicle Energy-saving – CONVENIENT’’ funded by the European Commission.
-
development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration-revue Internationale Du Froid, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The work has been done under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” founded by the European Commission.
-
theoretical modeling and experimental investigations for the improvement of the mechanical efficiency in sliding vane Rotary Compressors
Applied Energy, 2015Co-Authors: Giuseppe Bianchi, Roberto CipolloneAbstract:Positive displacement Compressors lead the market of compressed air production for industrial applications. Among them, sliding vane Rotary Compressors represent an energetically virtuous alternative to the current compression technologies. In the present work, the effects of compressor design parameters were investigated through a comprehensive approach that aimed at addressing more efficient machines to promote sliding vane Compressors as the key enabling technology in compressed air systems. A comprehensive mathematical model was developed to study the main phenomena occurring in this kind of Compressors. The model provides the cell volume evolution over a whole rotation during which filling, compression and discharge processes occur. The first and latter phases are described by the quasi-propagatory approach that represents the inertial, capacitive and resistive features of one-dimensional unsteady flows. The dynamics of the compressor blades led to four different arrangements inside the rotor slots while an analysis of the hydrodynamic lubrication established between blade tip and stator wall focused on the oil film thickness evolution to prevent dry contacts. An extensive experimental campaign on a mid-size industrial compressor allowed the model validation at different outlet pressure levels and revolution speeds using a direct measurement of mechanical power and the reconstruction of the indicator diagram from piezoelectric pressure transducers. The friction coefficient at the contact points between blades with stator and rotor was estimated in 0.065 and further improvements of the mechanical efficiency were eventually addressed considering the roles of compressor aspect ratio, revolution speed, and blade tilt. The first two theoretical optimizations might lead to an increase of the compressor efficiency of 2 and 9 percentage points respectively. On the other hand, acting on the blade tilt would not produce relevant improvements.
Giulio Contaldi - One of the best experts on this subject based on the ideXlab platform.
-
energy saving in sliding vane Rotary Compressors using pressure swirl oil atomizers
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2015Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:The work has been done under the FP7 project ‘‘Complete Vehicle Energy-saving – CONVENIENT’’ funded by the European Commission.
-
development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration-revue Internationale Du Froid, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The work has been done under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” founded by the European Commission.
-
Development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The present work highlights the energy saving potential of the lubricant fluid supplied in Sliding Vane Rotary air Compressors. A Lagrangian theoretical model of a sprayed oil injection technology assessed the cooling effect of the lubricant due to the high surface to volume ratio of the oil droplets and predicted a reduction of the indicated power. The model validation was carried out through a test campaign on a mid-size sliding vane compressor equipped with a series of pressure swirl atomizers. The oil injections took place along the axial length of the compressor. The reconstruction of the indicator diagram and the direct measurement of the mechanical power revealed a reduction of the energy consumption close to 7% using an injection pressure of 20 bar. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out to identify an optimal set of operative injection parameters.
-
performance enhancement in sliding vane Rotary Compressors through a sprayed oil injection technology
2014 Purdue Conferences. 22nd International Compressor Engineering Conference at Purdue., 2014Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio ContaldiAbstract:In Sliding Vane Rotary Compressors, as well as in most of positive displacement machines, the oil is injected to accomplish sealing and lubrication purposes. However, the oil injection could produce an additional outcome during the compression phase with a great saving potential from the energetic point of view. Being the air inside the cell at a higher temperature than the oil injected, a cooling effect could be achieved so decreasing the mechanical power required for the compression. At the moment, the oil is introduced inside the compressor vanes simply through a series of calibrated holes that are only able to produce solid jets. In this way any effective heat transfer is prevented, as demonstrated by p-V measurements inside the cells during the compression phase. In the current study, a theoretical model of a sprayed oil injection technology was developed and further experimentally validated. The oil was injected along the axial length of the compressor through a number of pressure swirl atomizers which produced a very fine spray. The conservation equations, solved with a Lagrangian approach, allowed to track the droplets evolution from the injection until the impingement onto the metallic surfaces of the vanes. The theoretical approach assessed the cooling effect due to the high surface to volume ratio of the droplets and a reduction of the indicated power was predicted. The model validation was carried out through a test campaign on an mid-size sliding vane compressor equipped with a series of pressure swirl injectors. The reconstruction of the indicator diagram as well as the direct measurements of torque and revolution speed revealed a reduction of the mechanical power absorbed close to 7% using an injection pressure of 20 bar. The model is in a satisfactory agreement with the tests and it also confirms the experimental trends available in the literature. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out in order to identify an optimal set of operating injection parameters.
-
energy saving in sliding vane Rotary Compressors
8th International Conference on Compressors and their Systems 2013, 2013Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:Electrical energy for producing compressed air in industrial contexts represents an important share of the overall electricity consumption: this figure accounts for 4-5 %.
Giuseppe Bianchi - One of the best experts on this subject based on the ideXlab platform.
-
energy saving potential in existing volumetric Rotary Compressors
Energy Procedia, 2015Co-Authors: Diego Vittorini, Giuseppe Bianchi, Roberto CipolloneAbstract:Abstract The issues of energy and Carbon saving in energy intensive sectors, along with that of energy generation from renewable sources, have been recently receiving a growing awareness, as they are perceived as the most effective ways to deal with global sustainability commitments. The Compressed Air Sector (CAS) accounts for a 10% worldwide electricity consumption, and thus is being re-thought as an area offering great opportunities for improvement. Considering that the compression is responsible for a 10-15% consumption, it is vital to pay attention to machines performances. An overview of present compressor technology is given and saving directions for Screw and Sliding Vanes machines are analyzed: interesting source of information was the Compressed Air and Gas Institute (CAGI), whose data have been processed, in order to obtain consistency with fixed reference pressures, and organized as a function of main operating parameters. The overall efficiency has been split and all different sub-terms (adiabatic, volumetric, mechanical, electrical, organic) considered separately. This has allowed a term-by-term evaluation of the margin for improvement. The heat recovery from the oil into mechanical energy via an Organic Rankine Cycle (ORC), together with the thermodynamic improvement during compression phase opens the way to a step change concerning the specific energy consumption.
-
friction power modeling and measurements in sliding vane Rotary Compressors
Applied Thermal Engineering, 2015Co-Authors: Giuseppe Bianchi, Roberto CipolloneAbstract:The authors acknowledge Ing. Enea Mattei S.p.A. and particularly its CEO, Dr. Giulio Contaldi, for continuous research funding and support. The work has been done also under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” funded by the European Commission.
-
energy saving in sliding vane Rotary Compressors using pressure swirl oil atomizers
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2015Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:The work has been done under the FP7 project ‘‘Complete Vehicle Energy-saving – CONVENIENT’’ funded by the European Commission.
-
development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration-revue Internationale Du Froid, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The work has been done under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” founded by the European Commission.
-
theoretical modeling and experimental investigations for the improvement of the mechanical efficiency in sliding vane Rotary Compressors
Applied Energy, 2015Co-Authors: Giuseppe Bianchi, Roberto CipolloneAbstract:Positive displacement Compressors lead the market of compressed air production for industrial applications. Among them, sliding vane Rotary Compressors represent an energetically virtuous alternative to the current compression technologies. In the present work, the effects of compressor design parameters were investigated through a comprehensive approach that aimed at addressing more efficient machines to promote sliding vane Compressors as the key enabling technology in compressed air systems. A comprehensive mathematical model was developed to study the main phenomena occurring in this kind of Compressors. The model provides the cell volume evolution over a whole rotation during which filling, compression and discharge processes occur. The first and latter phases are described by the quasi-propagatory approach that represents the inertial, capacitive and resistive features of one-dimensional unsteady flows. The dynamics of the compressor blades led to four different arrangements inside the rotor slots while an analysis of the hydrodynamic lubrication established between blade tip and stator wall focused on the oil film thickness evolution to prevent dry contacts. An extensive experimental campaign on a mid-size industrial compressor allowed the model validation at different outlet pressure levels and revolution speeds using a direct measurement of mechanical power and the reconstruction of the indicator diagram from piezoelectric pressure transducers. The friction coefficient at the contact points between blades with stator and rotor was estimated in 0.065 and further improvements of the mechanical efficiency were eventually addressed considering the roles of compressor aspect ratio, revolution speed, and blade tilt. The first two theoretical optimizations might lead to an increase of the compressor efficiency of 2 and 9 percentage points respectively. On the other hand, acting on the blade tilt would not produce relevant improvements.
Stefano Murgia - One of the best experts on this subject based on the ideXlab platform.
-
energy saving in sliding vane Rotary Compressors using pressure swirl oil atomizers
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2015Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:The work has been done under the FP7 project ‘‘Complete Vehicle Energy-saving – CONVENIENT’’ funded by the European Commission.
-
development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration-revue Internationale Du Froid, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The work has been done under the FP7 Project “Complete Vehicle Energy-Saving CONVENIENT” founded by the European Commission.
-
Development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane Rotary Compressors through theoretical and experimental methodologies
International Journal of Refrigeration, 2015Co-Authors: Giuseppe Bianchi, Stefano Murgia, Roberto Cipollone, Giulio ContaldiAbstract:The present work highlights the energy saving potential of the lubricant fluid supplied in Sliding Vane Rotary air Compressors. A Lagrangian theoretical model of a sprayed oil injection technology assessed the cooling effect of the lubricant due to the high surface to volume ratio of the oil droplets and predicted a reduction of the indicated power. The model validation was carried out through a test campaign on a mid-size sliding vane compressor equipped with a series of pressure swirl atomizers. The oil injections took place along the axial length of the compressor. The reconstruction of the indicator diagram and the direct measurement of the mechanical power revealed a reduction of the energy consumption close to 7% using an injection pressure of 20 bar. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out to identify an optimal set of operative injection parameters.
-
performance enhancement in sliding vane Rotary Compressors through a sprayed oil injection technology
2014 Purdue Conferences. 22nd International Compressor Engineering Conference at Purdue., 2014Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio ContaldiAbstract:In Sliding Vane Rotary Compressors, as well as in most of positive displacement machines, the oil is injected to accomplish sealing and lubrication purposes. However, the oil injection could produce an additional outcome during the compression phase with a great saving potential from the energetic point of view. Being the air inside the cell at a higher temperature than the oil injected, a cooling effect could be achieved so decreasing the mechanical power required for the compression. At the moment, the oil is introduced inside the compressor vanes simply through a series of calibrated holes that are only able to produce solid jets. In this way any effective heat transfer is prevented, as demonstrated by p-V measurements inside the cells during the compression phase. In the current study, a theoretical model of a sprayed oil injection technology was developed and further experimentally validated. The oil was injected along the axial length of the compressor through a number of pressure swirl atomizers which produced a very fine spray. The conservation equations, solved with a Lagrangian approach, allowed to track the droplets evolution from the injection until the impingement onto the metallic surfaces of the vanes. The theoretical approach assessed the cooling effect due to the high surface to volume ratio of the droplets and a reduction of the indicated power was predicted. The model validation was carried out through a test campaign on an mid-size sliding vane compressor equipped with a series of pressure swirl injectors. The reconstruction of the indicator diagram as well as the direct measurements of torque and revolution speed revealed a reduction of the mechanical power absorbed close to 7% using an injection pressure of 20 bar. The model is in a satisfactory agreement with the tests and it also confirms the experimental trends available in the literature. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out in order to identify an optimal set of operating injection parameters.
-
energy saving in sliding vane Rotary Compressors
8th International Conference on Compressors and their Systems 2013, 2013Co-Authors: Roberto Cipollone, Stefano Murgia, Giulio Contaldi, Giuseppe Bianchi, Gianluca Valenti, Tommaso CalviAbstract:Electrical energy for producing compressed air in industrial contexts represents an important share of the overall electricity consumption: this figure accounts for 4-5 %.
Jianhua Wu - One of the best experts on this subject based on the ideXlab platform.
-
numerical investigation on vapor liquid two phase compression in the cylinder of Rotary Compressors
Applied Thermal Engineering, 2020Co-Authors: Yongsheng Lian, Jianhua WuAbstract:Abstract Liquid slugging often appears during the process of start-up and defrost due to the existence of liquid in the compression chamber. As the pressure shoots up to a very high values under the liquid slugging conditions, it threatens the reliability of Rotary Compressors. In this paper, a newly developed model to predict the pressure jump in the cylinder during the liquid slugging conditions is proposed, and two-phase compression characteristics are investigated. This model considers refrigerant phase change, kinetic energy of refrigerant and heat exchange between refrigerant and the wall of compression chamber. Comparisons are made with experimental study of liquid slugging using R290 refrigerant. The simulation results show good agreement with experimental results in terms of pressure variation. Effects of initial gas fraction, rotation speed of crank and types of refrigerant on the liquid slugging are investigated. This study shows that by reducing rotation speed or increasing the gas fraction, the pressure jump in the cylinder can be effectively eliminated. It also shows that liquid slugging in the cylinder using R290 is weaker than R22 and R410A under the same conditions.
-
Thermal analysis of oil sump and compression unit in a Rotary compressor
Applied Thermal Engineering, 2020Co-Authors: Jianhua WuAbstract:Abstract Thermal analysis of the oil sump and compression unit in a hermetic Rotary compressor is important for enhancing its performance and reliability. In this study, the temperature distribution, heat-transfer mechanism, and heat balance of the oil sump and compression unit in a Rotary compressor were analyzed using the 3D computational fluid dynamics (CFD) fluid-solid coupled model. Considering the practical characteristics of the Rotary compressor, some special treatments are proposed for the simulation model. Instead of using empirical formulations, heat-transfer coefficients in the upside of the main bearing and compressor shell were obtained using the 3D CFD simulation model; the dynamic process in the suction chamber and compression chamber was considered to be static and the oil film in the inner wall of the cylinder, rib effect of the A-frame structure at the bottom of the compressor shell, and friction loss in the side of the sliding vane were considered. The simulation results showed good agreement with experimental results. We expect that these analytical results would be of great use in further understanding the temperature distribution and heat-transfer mechanism of oil sumps and compression units and also provide guidelines for improving the performance and reliability of Rotary Compressors.
-
Experimental study on the tribological characteristic of vane–roller interface of HC290 Rotary compressor with mineral oil
International Journal of Refrigeration-revue Internationale Du Froid, 2018Co-Authors: Zhenhua Chen, Jianhua Wu, Gaimin LiAbstract:Abstract As a natural refrigerant, HC290 is considered as an excellent long-term alternative refrigerant applied in room air-conditioners (RAC). In this paper, the experimental study on tribological characteristics of the vane–roller friction pair in HC290 Rotary Compressors was carried out and friction coefficients and wear depths were measured under the pure HC290 atmosphere, pure mineral oil and HC290/mineral oil mixture environment, respectively. In order to obtain the experimental conditions as close as possible to the actual operating conditions of a HC290 Rotary compressor, the mass-produced vanes and rollers were adopted, and all tests were performed with a high-pressure tribometer under various sliding speeds, loads and temperatures which were set to simulate the different actual operating conditions of Rotary Compressors. Furthermore, the scuffing tests were performed and the Scanning Electron Microscopic has been used to investigate morphological changes occurred after test. The experiment results with the HC290/mineral oil mixture showed that better anti-scuffing ability but a higher friction coefficient of vane–roller interface were acquired compared to HFC410A/polyolester. The results obtained here may provide some guides for further investigations on tribological characteristics of the vane–roller interface of HC290 Rotary Compressors.
-
a cfd model for the oil discharge ratio in Rotary Compressors
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2015Co-Authors: Jianhua Wu, Gang Wang, Jiehao Hu, Jie Zhang, Ang ChenAbstract:The research on oil discharge ratio (ODR) of Rotary Compressors used for room air conditioners is very important to improve the performance and reliability of the Compressors and their systems. This paper presents a detailed computational fluid dynamics (CFD) simulation model for the refrigerant gas flow and oil droplet flow within the shell of the compressor, which is used for investigating ODR of the compressor subjected to design changes or under different operating speeds. The geometry of the Rotary compressor and its oil separating burden was presented. The CFD simulation is based on the discrete phase model (DPM). The oil droplet size distribution was defined by the Rosin–Rammler diameter distribution method. The boundary conditions of the refrigerant gas and oil droplets were established. Validation of the CFD model has been made by measuring ODR of a Rotary compressor used in the high efficiency air room conditioner for different design configurations and an inverter Rotary compressor with R410A. ...
-
dynamic behaviors of the crankshafts in single cylinder and twin cylinder Rotary Compressors
International Journal of Refrigeration-revue Internationale Du Froid, 2014Co-Authors: Jianhua Wu, Ang Chen, Haifeng Zhang, Yanzhong LiAbstract:Abstract Refrigeration Rotary Compressors are widely used in air-conditioners. A Rotary compressor has a special rotor-bearing system, since the elastic cantilevered crankshaft is under dynamic transverse forces on different planes. The large deformation of the crankshaft would affect the thickness of the oil film, wear the bearings down or even induce the rotor-to-stator rubs. It is considered as a non-linear fluid–structure interaction problem. To ensure the compressor operating well, the dynamic behaviors of both single-cylinder and twin-cylinder Compressors' crankshafts at various speeds are analyzed. The influence of configuration of balancers on the reliability of rotor system is investigated for the further. Calculation results suggest that the vulnerable sections of crankshaft vary with the rotational speed. It is also found that 80% of the dynamic balance is the optimum design condition to reduce the transverse forces on crankshaft and the wear-out of journal bearings.
