The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform

Lemo Vince - One of the best experts on this subject based on the ideXlab platform.

  • Detailed Experimental and Model-Based Analysis of a Swash-Plate Piston Expander for ORC Application
    'Frontiers Media SA', 2020
    Co-Authors: Oudkerk Jean-françois, Lemo Vince
    Abstract:

    peer reviewedaudience: researcher, professional, studentA 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 steady state points were measured. With these measurements, performance maps were generated to point out the influence of rotational speed and levels of pressure on mechanical power and isentropic efficiency. These maps have highlighted the existence of an optimal rotational speed of around 3000 RPM maximizing the mechanical power, while the speed that maximizes the isentropic efficiency lies between 2000 and 2500 RPM. The maximal mechanical power and isentropic efficiency were 2.8 kW and 53%, respectively. Then the measurements were used to analyze the losses. This analysis has shown that, under the expansion and compression limit, the theoretical isentropic efficiency has values comprised between 90% and 70% for pressure ratios of 7 to 12. The filling factor affects the isentropic efficiency for low rotational speeds and low pressure ratios. Indeed, indicated isentropic efficiency is around 60% for 1000 RPM and around 75% for 4000 RPM. These values stay quite constant with the pressure ratio. Finally, a mechanical efficiency comprised between 40% and 90% was observed, which lowers the isentropic efficiency to values comprised between 30% and 53%. Finally, a model based on energy and mass conservation inside a cylinder volume was successfully calibrated and was able to predict mass flow rate, mechanical power and Exhaust Temperature with good agreement. This model has enabled disaggregation of the influence of pressure drops and leakages on the filling factor, then on the isentropic efficiency. This analysis has shown that pressure drops mainly affect the compactness of the expander, and not so much the isentropic efficiency (except for low rotational speeds where pressure drops can lower the isentropic efficiency by 14%). In contrary, leakages have a strong impact. The importance of the different sources of losses varies with the speed. For the optimal speed of 2500 RPM, under-expansion and compression have the strongest impact, followed by mechanical losses, leakages and pressure drops, respectively

  • Detailed Experimental and Model-Based Analysis of a Swash-Plate Piston Expander for ORC Application
    2020
    Co-Authors: Oudkerk Jean-françois, Lemo Vince
    Abstract:

    A 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 steady state points were measured. With these measurements, performance maps were generated to point out the influence of rotational speed and levels of pressure on mechanical power and isentropic efficiency. These maps have highlighted the existence of an optimal rotational speed of around 3000 RPM maximizing the mechanical power, while the speed that maximizes the isentropic efficiency lies between 2000 and 2500 RPM. The maximal mechanical power and isentropic efficiency were 2.8 kW and 53%, respectively. Then the measurements were used to analyze the losses. This analysis has shown that, under the expansion and compression limit, the theoretical isentropic efficiency has values comprised between 90% and 70% for pressure ratios of 7 to 12. The filling factor affects the isentropic efficiency for low rotational speeds and low pressure ratios. Indeed, indicated isentropic efficiency is around 60% for 1000 RPM and around 75% for 4000 RPM. These values stay quite constant with the pressure ratio. Finally, a mechanical efficiency comprised between 40% and 90% was observed, which lowers the isentropic efficiency to values comprised between 30% and 53%. Finally, a model based on energy and mass conservation inside a cylinder volume was successfully calibrated and was able to predict mass flow rate, mechanical power and Exhaust Temperature with good agreement. This model has enabled disaggregation of the influence of pressure drops and leakages on the filling factor, then on the isentropic efficiency. This analysis has shown that pressure drops mainly affect the compactness of the expander, and not so much the isentropic efficiency (except for low rotational speeds where pressure drops can lower the isentropic efficiency by 14%). In contrary, leakages have a strong impact. The importance of the different sources of losses varies with the speed. For the optimal speed of 2500 RPM, under-expansion and compression have the strongest impact, followed by mechanical losses, leakages and pressure drops, respectively.Peer reviewe

Oudkerk Jean-françois - One of the best experts on this subject based on the ideXlab platform.

  • Detailed Experimental and Model-Based Analysis of a Swash-Plate Piston Expander for ORC Application
    'Frontiers Media SA', 2020
    Co-Authors: Oudkerk Jean-françois, Lemo Vince
    Abstract:

    peer reviewedaudience: researcher, professional, studentA 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 steady state points were measured. With these measurements, performance maps were generated to point out the influence of rotational speed and levels of pressure on mechanical power and isentropic efficiency. These maps have highlighted the existence of an optimal rotational speed of around 3000 RPM maximizing the mechanical power, while the speed that maximizes the isentropic efficiency lies between 2000 and 2500 RPM. The maximal mechanical power and isentropic efficiency were 2.8 kW and 53%, respectively. Then the measurements were used to analyze the losses. This analysis has shown that, under the expansion and compression limit, the theoretical isentropic efficiency has values comprised between 90% and 70% for pressure ratios of 7 to 12. The filling factor affects the isentropic efficiency for low rotational speeds and low pressure ratios. Indeed, indicated isentropic efficiency is around 60% for 1000 RPM and around 75% for 4000 RPM. These values stay quite constant with the pressure ratio. Finally, a mechanical efficiency comprised between 40% and 90% was observed, which lowers the isentropic efficiency to values comprised between 30% and 53%. Finally, a model based on energy and mass conservation inside a cylinder volume was successfully calibrated and was able to predict mass flow rate, mechanical power and Exhaust Temperature with good agreement. This model has enabled disaggregation of the influence of pressure drops and leakages on the filling factor, then on the isentropic efficiency. This analysis has shown that pressure drops mainly affect the compactness of the expander, and not so much the isentropic efficiency (except for low rotational speeds where pressure drops can lower the isentropic efficiency by 14%). In contrary, leakages have a strong impact. The importance of the different sources of losses varies with the speed. For the optimal speed of 2500 RPM, under-expansion and compression have the strongest impact, followed by mechanical losses, leakages and pressure drops, respectively

  • Detailed Experimental and Model-Based Analysis of a Swash-Plate Piston Expander for ORC Application
    2020
    Co-Authors: Oudkerk Jean-françois, Lemo Vince
    Abstract:

    A 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 steady state points were measured. With these measurements, performance maps were generated to point out the influence of rotational speed and levels of pressure on mechanical power and isentropic efficiency. These maps have highlighted the existence of an optimal rotational speed of around 3000 RPM maximizing the mechanical power, while the speed that maximizes the isentropic efficiency lies between 2000 and 2500 RPM. The maximal mechanical power and isentropic efficiency were 2.8 kW and 53%, respectively. Then the measurements were used to analyze the losses. This analysis has shown that, under the expansion and compression limit, the theoretical isentropic efficiency has values comprised between 90% and 70% for pressure ratios of 7 to 12. The filling factor affects the isentropic efficiency for low rotational speeds and low pressure ratios. Indeed, indicated isentropic efficiency is around 60% for 1000 RPM and around 75% for 4000 RPM. These values stay quite constant with the pressure ratio. Finally, a mechanical efficiency comprised between 40% and 90% was observed, which lowers the isentropic efficiency to values comprised between 30% and 53%. Finally, a model based on energy and mass conservation inside a cylinder volume was successfully calibrated and was able to predict mass flow rate, mechanical power and Exhaust Temperature with good agreement. This model has enabled disaggregation of the influence of pressure drops and leakages on the filling factor, then on the isentropic efficiency. This analysis has shown that pressure drops mainly affect the compactness of the expander, and not so much the isentropic efficiency (except for low rotational speeds where pressure drops can lower the isentropic efficiency by 14%). In contrary, leakages have a strong impact. The importance of the different sources of losses varies with the speed. For the optimal speed of 2500 RPM, under-expansion and compression have the strongest impact, followed by mechanical losses, leakages and pressure drops, respectively.Peer reviewe

Spoof-tuomi Kirsi - One of the best experts on this subject based on the ideXlab platform.

  • Different methods to improve the Exhaust gas Temperature in modern stage V 0ff-road diesel engine over transient emission cycles
    'SAE International', 2020
    Co-Authors: Laure Mika, Karhu Toomas, Niemi Seppo, Laivola Miika, Ja Ekma, Spoof-tuomi Kirsi
    Abstract:

    This paper presents several methods to improve the Exhaust gas Temperature of a modern diesel engine. A high Exhaust gas Temperature is needed to improve the after-treatment system efficiency and particulate filter regeneration in low engine loads. This study is based on experimental measurements of two Stage 5 level off-road diesel engines. The effect of the different heating methods determined over steady state runs and emission and performance are presented with standard emission transient test procedure (NRTC). In the first step of the study, an intake air restriction and an Exhaust gas restriction method are compared. The intake restriction produces better fuel economy over the measuring cycle. However, with the Exhaust restriction, higher Exhaust gas Temperature can be achieved in low engine loads. In the second phase of study, the intake air restriction method was implemented in the research engine. In addition, active waste gate controlling, and injection retardation methods were taken in use for heating purposes. The engine performance was determined with normal calibration and with high Exhaust Temperature calibration. The differences to the Exhaust Temperature, engine performance and emission were presented in transient emission cycle NRTC.fi=vertaisarvioitu|en=peerReviewed

Hossai A. K. - One of the best experts on this subject based on the ideXlab platform.

  • Modified Selective Non-Catalytic Reduction System to Reduce NOx Gas Emission in Biodiesel Powered Engines
    2020
    Co-Authors: Masera Kemal, Hossai A. K.
    Abstract:

    Biodiesel is considered as one of the attractive alternatives to fossil diesel fuel. Although biodiesels reduces most of the harmful gas emissions, they normally releases higher NOx emissions compared to fossil diesel. The Selective Catalytic Reduction (SCR) is a well-known technique used in the OEM industry to mitigate NOx emission. However, this technique may not be suitable for application in low power density engines due to back pressure and clogging issues. On the other hand, Selective Non-Catalytic Reduction (SNCR) is used in relatively large combustion operations ie. boilers and incinerators. The main disadvantage of SNCR technique is the high Temperature window for diesel engine Exhaust Temperature. This study introduces a new design concept, which is a combination of SCR and SNCR systems, for low power density diesel engines. The developed after-treatment system composed of two main parts, injection-expansion pipe and swirl chamber. The working principle is providing maximum mixing of the injected fluid and Exhaust gas in the expansion chamber, then creating a maximum turbulence in the swirl chamber. In this regard, NOx emission can be reduced at relatively lower Exhaust Temperatures without using any catalyst. The CFD models of three design candidates were examined in terms of velocity magnitudes, turbulence intensity and particle residence time to select the optimum physical dimensions. The selected design was manufactured and installed to Exhaust system of a 1.3 litre diesel engine. Two fluids distilled water and urea-water solution were injected separately at the same flow rate of 375 ml/min. Exhaust gas emissions of fossil diesel, sheep fat biodiesel – waste cooking oil biodiesel blend and chicken fat – cottonseed biodiesel blend were tested. No significant changes in CO2 and HC emissions were observed. However, it was found that distilled water injection reduced CO and NO emissions by about 10% and 6% for fossil diesel; and by about 9% and 7% for biodiesels operation respectively. The urea-water injection led to reductions in CO and NO emissions by about 60% and 13% for fossil diesel; and by about 45% and 15% for biodiesels respectively

Laure Mika - One of the best experts on this subject based on the ideXlab platform.

  • Different methods to improve the Exhaust gas Temperature in modern stage V 0ff-road diesel engine over transient emission cycles
    'SAE International', 2020
    Co-Authors: Laure Mika, Karhu Toomas, Niemi Seppo, Laivola Miika, Ja Ekma, Spoof-tuomi Kirsi
    Abstract:

    This paper presents several methods to improve the Exhaust gas Temperature of a modern diesel engine. A high Exhaust gas Temperature is needed to improve the after-treatment system efficiency and particulate filter regeneration in low engine loads. This study is based on experimental measurements of two Stage 5 level off-road diesel engines. The effect of the different heating methods determined over steady state runs and emission and performance are presented with standard emission transient test procedure (NRTC). In the first step of the study, an intake air restriction and an Exhaust gas restriction method are compared. The intake restriction produces better fuel economy over the measuring cycle. However, with the Exhaust restriction, higher Exhaust gas Temperature can be achieved in low engine loads. In the second phase of study, the intake air restriction method was implemented in the research engine. In addition, active waste gate controlling, and injection retardation methods were taken in use for heating purposes. The engine performance was determined with normal calibration and with high Exhaust Temperature calibration. The differences to the Exhaust Temperature, engine performance and emission were presented in transient emission cycle NRTC.fi=vertaisarvioitu|en=peerReviewed