The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Ji Yeon Song - One of the best experts on this subject based on the ideXlab platform.

  • high performance strategy of a simulated moving bed chromatography by simultaneous control of product and feed streams under Maximum Allowable Pressure drop
    Journal of Chromatography A, 2016
    Co-Authors: Ji Yeon Song
    Abstract:

    In this study, a novel operating strategy was developed to improve the separation performance of simulated moving bed (SMB) chromatography by the simultaneous control of product outlet streams and feed inlet stream (SimCon). The SimCon operation can achieve a high separation performance without exceeding the Maximum Allowable Pressure drop in an SMB system. The SimCon operation consisted of three steps within a single switching period: the initial, middle, and last steps. The extract port and feed-inlet port were closed at the initial step, but the raffinate port was closed at the last step. Therefore, in the SimCon strategy, we introduce two additional operating variables in a switching period, namely the middle time and middle length. In the SimCon operation, the middle step is a key factor to achieving a good separation performance because concentration profiles can be well controlled by two new middle-step variables. The SimCon operation showed outstanding results compared with those of the corresponding conventional SMB and other stream-control strategies in terms of purity, recovery, productivity, and eluent consumption. Because the SimCon operation can be operated with smaller flow and Pressure fluctuations than other flow-rate-control strategies and improves the column efficiency, it is expected that the strategy can be practically adapted to real SMB processes with a good separation performance.

  • Combined operation of outlet streams swing with partial-feed in a simulated moving bed
    Korean Journal of Chemical Engineering, 2016
    Co-Authors: Ji Yeon Song
    Abstract:

    The operational strategy of outlet streams swing (OSS) operation combined with partial-feed (PF) operation, OSS-PF, was studied under the constraint of Maximum Allowable Pressure and flow-rate. Its separation performance and dynamic behavior were compared with those of OSS operation and conventional simulated moving bed (SMB) chromatography. During OSS-PF operation, the switching period consisted of two steps; raffinate was produced during the closed condition of extract node and feed node in the first step, while extracts were produced and feeds were injected during the closed condition of raffinate node in the second step. As a result, OSS-PF operation could be performed under the Allowable Maximum flow-rate in the corresponding conventional SMB without generating an additional Pressure drop at the adsorbent bed, which was different from OSS operation. OSS-PF operation successfully improved the separation performance of the conventional SMB with regard to extract purity, raffinate recovery and raffinate productivity with equivalent eluent consumption. The step ratio during a switching period worked as one of important operating variables in separation performance. The dynamic behavior of OSS-PF operation was analyzed and compared with that of OSS and conventional SMB using simulated concentration profiles in the fluid phase.

Yousef M Abdel-rahim - One of the best experts on this subject based on the ideXlab platform.

  • Zero-dimensional model for a 4-stroke, direct injection, variable compression ratio for Maximum torque
    2020
    Co-Authors: M.m. Abou Al-sood, Yousef M Abdel-rahim, Ahmed
    Abstract:

    A zero-dimensional model for simulation the performance of a four-stroke direct-injection (DI) diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and NOx formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions were conducted. Comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective target of constant Maximum brake torque. The optimization analysis is performed under the constrain that the Maximum Pressure and temperature inside the cylinder not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant compression ratio, rc).Varying compression ratio is optimized with the previous condition. Results indicated that optimum brake torque is achieved when the value of, rc, ranged between 16.4 and 19.3, where the brake specific fuel consumption, bsfc, and soot emission are reduced by about 4.6% and 12 %, respectively. Furthermore, the brake torque is increases by about 5.4%; NOx, Maximum Pressure (pmax) , and Maximum temperature (Tmax) are increased by about 90.7 %, 10.3% and 3.6 %, respectively.

  • Rapid thermodynamic simulation model for optimum performance of a four-stroke, direct-injection, and variable-compression-ratio diesel engine
    International Journal of Energy and Environmental Engineering, 2012
    Co-Authors: Maher M Abou Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahim
    Abstract:

    A thermodynamic simulation model for the performance of a four-stroke, direct-injection diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and oxides of nitrogen (NO_x) formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions, were conducted. The comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective targets such as constant minimum brake-specific fuel consumption and constant Maximum torque. The optimization analysis is performed under the constraint that the Maximum Pressure and temperature inside the cylinder do not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant compression ratio).The varying compression ratio is optimized with each of the previous conditions separately. Results indicated that varying the compression ratio to achieve previous targets leads to saving fuel consumption, higher brake efficiency and power, and reduction in soot emission from the engine. Also, an increase in NO_x is noticed at low speed. This drawback is considerable and can be overcome by reducing the operation speed range.

  • Optimum Compression Ratio Variation of 4-Stroke, Direct Injection Diesel Engine for Optimum Performance
    Volume 4: Energy Systems Analysis Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy Parts A and B, 2011
    Co-Authors: M.m. Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahim
    Abstract:

    A thermodynamic model for simulation the performance of a four-stroke direct-injection (DI) diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and NOx formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions were conducted. Comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective target of constant minimum brake specific fuel consumption (bsfc). The optimization analysis is performed under the constrain that the Maximum Pressure and temperature inside the cylinder not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant rc ). Varying compression ratio is optimized with the previous condition. Results indicated that, at the values of rc ranged between 16.4 and 17.8, the optimum bsfc is attained with an increase in brake power by about 3.8%, while the bsfc and soot emission are reduced by about 4.4% and 21%, respectively. In addition to an increase in NOx , Maximum Pressure (pmax ), and Maximum temperature (Tmax ) by about 75%, 6% and 4.3%, respectively.Copyright © 2011 by ASME

Maher M Abou Abou Al-sood - One of the best experts on this subject based on the ideXlab platform.

  • Rapid thermodynamic simulation model for optimum performance of a four-stroke, direct-injection, and variable-compression-ratio diesel engine
    International Journal of Energy and Environmental Engineering, 2012
    Co-Authors: Maher M Abou Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahim
    Abstract:

    A thermodynamic simulation model for the performance of a four-stroke, direct-injection diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and oxides of nitrogen (NO_x) formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions, were conducted. The comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective targets such as constant minimum brake-specific fuel consumption and constant Maximum torque. The optimization analysis is performed under the constraint that the Maximum Pressure and temperature inside the cylinder do not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant compression ratio).The varying compression ratio is optimized with each of the previous conditions separately. Results indicated that varying the compression ratio to achieve previous targets leads to saving fuel consumption, higher brake efficiency and power, and reduction in soot emission from the engine. Also, an increase in NO_x is noticed at low speed. This drawback is considerable and can be overcome by reducing the operation speed range.

Mahmoud Ahmed - One of the best experts on this subject based on the ideXlab platform.

  • Rapid thermodynamic simulation model for optimum performance of a four-stroke, direct-injection, and variable-compression-ratio diesel engine
    International Journal of Energy and Environmental Engineering, 2012
    Co-Authors: Maher M Abou Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahim
    Abstract:

    A thermodynamic simulation model for the performance of a four-stroke, direct-injection diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and oxides of nitrogen (NO_x) formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions, were conducted. The comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective targets such as constant minimum brake-specific fuel consumption and constant Maximum torque. The optimization analysis is performed under the constraint that the Maximum Pressure and temperature inside the cylinder do not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant compression ratio).The varying compression ratio is optimized with each of the previous conditions separately. Results indicated that varying the compression ratio to achieve previous targets leads to saving fuel consumption, higher brake efficiency and power, and reduction in soot emission from the engine. Also, an increase in NO_x is noticed at low speed. This drawback is considerable and can be overcome by reducing the operation speed range.

  • Optimum Compression Ratio Variation of 4-Stroke, Direct Injection Diesel Engine for Optimum Performance
    Volume 4: Energy Systems Analysis Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy Parts A and B, 2011
    Co-Authors: M.m. Abou Al-sood, Mahmoud Ahmed, Yousef M Abdel-rahim
    Abstract:

    A thermodynamic model for simulation the performance of a four-stroke direct-injection (DI) diesel engine is developed. The simulation model includes detailed sub-models for fuel burning rate, combustion products, thermodynamic properties of working fluid, heat transfer, fluid flow, and both soot and NOx formation mechanisms. To validate the model, comparisons between experimental and predicted results for different engines, operating under different conditions were conducted. Comparisons show that there is a good concurrence between measured and predicted values. An optimization analysis is conducted for seeking an optimum variation of compression ratio to achieve pre-set objective target of constant minimum brake specific fuel consumption (bsfc). The optimization analysis is performed under the constrain that the Maximum Pressure and temperature inside the cylinder not exceed the Maximum Allowable Pressure and temperature of the conventional engine (constant rc ). Varying compression ratio is optimized with the previous condition. Results indicated that, at the values of rc ranged between 16.4 and 17.8, the optimum bsfc is attained with an increase in brake power by about 3.8%, while the bsfc and soot emission are reduced by about 4.4% and 21%, respectively. In addition to an increase in NOx , Maximum Pressure (pmax ), and Maximum temperature (Tmax ) by about 75%, 6% and 4.3%, respectively.Copyright © 2011 by ASME

J K Peng - One of the best experts on this subject based on the ideXlab platform.

  • dynamics of cryogenic hydrogen storage in insulated Pressure vessels for automotive applications
    International Journal of Hydrogen Energy, 2008
    Co-Authors: R K Ahluwalia, J K Peng
    Abstract:

    Abstract A dynamic model is used to characterize cryogenic H 2 storage in an insulated Pressure vessel that can flexibly hold liquid H 2 and compressed H 2 at 350 bar. A double-flow refueling device is needed to ensure that the tank can be consistently refueled to its theoretical capacity regardless of the initial conditions. Liquid H 2 charged into the tank is stored as supercritical fluid if the initial tank temperature is >120 K and as a subcooled liquid if it is 2 is stored as a supercritical fluid, liquid H 2 will form as H 2 is withdrawn and will further transform to a two-phase mixture and ultimately to a superheated gas. The recoverable fraction of the total stored inventory depends on the minimum H 2 delivery Pressure and the power rating of the heater. The dormancy of cryogenic H 2 is a function of the Maximum Allowable Pressure and the Pressure of stored H 2 ; the evaporative losses cannot deplete H 2 from the tank beyond 64% of the theoretical storage capacity.