The Experts below are selected from a list of 336 Experts worldwide ranked by ideXlab platform
Nadeem Ahmed Sheikh - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Maisotsenko humid air bottoming cycle employing mixed flow air saturator
Heat and Mass Transfer, 2019Co-Authors: Rasikh Tariq, Nadeem Ahmed Sheikh, Ali Bassam, Jesus XamánAbstract:Maisotsenko Humid Air Bottoming Cycle (MHABC) is a viable option for the waste heat recovery of gas turbine topping cycle to attain a higher efficiency point of the combined cycle power plant; thus, having a potential of lower CO2 emissions towards environment. In this work, instead of the typically proposed counter flow configuration of the air saturator, a novel mixed flow configuration is proposed. The proposed configuration uses a hybrid cross-flow and a regenerative counter-flow heat and mass exchanger (HMX). This hybrid HMX is numerically simulated to estimate optimal amount of saturated air which can lead to maximum efficiency and power output. The mathematical model of the mixed flow configuration HMX based air saturator is developed by applying mass and energy balance laws on a selected control volume. The results of the air saturator are initially validated using previously published experimental data for air cooling applications. Furthermore, simulations for high-pressure operations suitable for power generation are performed and a parametric analysis shows that optimal mass flow rate ratio between the working air in the dry channel and incoming air for cross-flow part is 0.65. Optimal mass flow ratio between the working air wet channel and working air dry channel for the counter-flow part is 0.5. The integration of hybrid air saturator in MHABC can yield a maximum of ~57 MW of output work and ~42% of thermal efficiency. The proposed system can achieve a 7% increment in total output work, and 9% increment in thermal efficiency as compared to the counter-flow configuration as an air saturator in the bottoming cycle. Furthermore, the proposed system has ~55% fewer carbon footprint as compared to counter-flow configuration alone as an air saturator.
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an innovative air saturator for humidification dehumidification desalination application
Applied Energy, 2018Co-Authors: Rasikh Tariq, Nadeem Ahmed Sheikh, J Xaman, A BassamAbstract:Abstract In this work, an innovative and novel integrated Maisotsenko cycle-based air saturator is proposed as a humidifier in humidification-dehumidification type desalination system. The proposed system has unique flow characteristic within the heat and mass exchanger to maximize air saturation at the exit of humidifier; thus, maximizing the potential for desalination. The process of air saturation in the wet channel is altered by including an infiltration flow from the dry passes on to the wet passes of the air saturator. A detailed mathematical model is developed and solved through an iterative procedure, and the performance of the system is deduced based on fresh water production rate, recovery ratio, and gain-output-ratio. It is reported that in the proposed design an infiltration rate of 0.6 corresponds to maximum water evaporation rate and justified pump and blower work. Comparative analysis has shown that the proposed novel system configuration offers 30% higher fresh water productivity, 46% higher recovery ratio, and 11% higher gain-output-ratio as compared to conventional direct-contact humidifier-based desalination plant. Performance investigation analysis is carried out for 31 different cities of the world to determine the applicability of the proposed system under different climatic conditions. Economic estimation has shown that the cost of desalinated water using proposed system is 0.030 USD/liter which is 14% lower than the conventional humidification-dehumidification desalination system. Furthermore, environmental analysis has shown that the proposed system has ∼7% lower carbon footprints. It is concluded that the proposed system offers energy-efficient, cost-effective and environmental friendly method of desalination and can be used in most parts of the world.
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numerical heat transfer analysis of maisotsenko humid air bottoming cycle a study towards the optimization of the air water mixture at bottoming turbine inlet
Applied Thermal Engineering, 2018Co-Authors: Rasikh Tariq, Nadeem Ahmed SheikhAbstract:Abstract Maisotsenko Humid Air Bottoming Cycle (MHABC) is a recently proposed waste heat recovery unit for gas turbine topping cycle. An air saturator is used for the waste heat recovery and air humidification purposes in the bottoming cycle. The humid air is used in bottoming cycle turbine. In this work, detailed heat transfer analysis of the MHABC is proposed along with the evaluation of degree of humidification and energy recovery. The air saturator is numerically simulated after the development of governing ordinary differential equations for the temperature and humidity distribution of the working air. The governing differential equations of air saturator are discretized using first order accurate finite difference scheme and simulated using MATLAB. The results for the air saturator are initially validated using inlet ambient pressure conditions at standard atmospheric conditions. The upper section of the bottoming cycle is modeled using analytical NTU method. The overall performance of the plant with MHABC is also compared with results reported in literature. Temperature and humidity levels for working air is presented. These results show that the proposed MHABC configuration gives maximum work output (58 MW) and efficiency (∼34%) at the air saturator exit relative humidity of 70%. Corresponding to the maximum system output conditions, the dew point effectiveness of the air saturator is noted at 0.8 with 32% relative humidity at the bottoming turbine inlet. While the air split ratio of 50% between lower air saturator and heat exchanger gives more than 8 MW of waste heat recovery.
Rasikh Tariq - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Maisotsenko humid air bottoming cycle employing mixed flow air saturator
Heat and Mass Transfer, 2019Co-Authors: Rasikh Tariq, Nadeem Ahmed Sheikh, Ali Bassam, Jesus XamánAbstract:Maisotsenko Humid Air Bottoming Cycle (MHABC) is a viable option for the waste heat recovery of gas turbine topping cycle to attain a higher efficiency point of the combined cycle power plant; thus, having a potential of lower CO2 emissions towards environment. In this work, instead of the typically proposed counter flow configuration of the air saturator, a novel mixed flow configuration is proposed. The proposed configuration uses a hybrid cross-flow and a regenerative counter-flow heat and mass exchanger (HMX). This hybrid HMX is numerically simulated to estimate optimal amount of saturated air which can lead to maximum efficiency and power output. The mathematical model of the mixed flow configuration HMX based air saturator is developed by applying mass and energy balance laws on a selected control volume. The results of the air saturator are initially validated using previously published experimental data for air cooling applications. Furthermore, simulations for high-pressure operations suitable for power generation are performed and a parametric analysis shows that optimal mass flow rate ratio between the working air in the dry channel and incoming air for cross-flow part is 0.65. Optimal mass flow ratio between the working air wet channel and working air dry channel for the counter-flow part is 0.5. The integration of hybrid air saturator in MHABC can yield a maximum of ~57 MW of output work and ~42% of thermal efficiency. The proposed system can achieve a 7% increment in total output work, and 9% increment in thermal efficiency as compared to the counter-flow configuration as an air saturator in the bottoming cycle. Furthermore, the proposed system has ~55% fewer carbon footprint as compared to counter-flow configuration alone as an air saturator.
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an innovative air saturator for humidification dehumidification desalination application
Applied Energy, 2018Co-Authors: Rasikh Tariq, Nadeem Ahmed Sheikh, J Xaman, A BassamAbstract:Abstract In this work, an innovative and novel integrated Maisotsenko cycle-based air saturator is proposed as a humidifier in humidification-dehumidification type desalination system. The proposed system has unique flow characteristic within the heat and mass exchanger to maximize air saturation at the exit of humidifier; thus, maximizing the potential for desalination. The process of air saturation in the wet channel is altered by including an infiltration flow from the dry passes on to the wet passes of the air saturator. A detailed mathematical model is developed and solved through an iterative procedure, and the performance of the system is deduced based on fresh water production rate, recovery ratio, and gain-output-ratio. It is reported that in the proposed design an infiltration rate of 0.6 corresponds to maximum water evaporation rate and justified pump and blower work. Comparative analysis has shown that the proposed novel system configuration offers 30% higher fresh water productivity, 46% higher recovery ratio, and 11% higher gain-output-ratio as compared to conventional direct-contact humidifier-based desalination plant. Performance investigation analysis is carried out for 31 different cities of the world to determine the applicability of the proposed system under different climatic conditions. Economic estimation has shown that the cost of desalinated water using proposed system is 0.030 USD/liter which is 14% lower than the conventional humidification-dehumidification desalination system. Furthermore, environmental analysis has shown that the proposed system has ∼7% lower carbon footprints. It is concluded that the proposed system offers energy-efficient, cost-effective and environmental friendly method of desalination and can be used in most parts of the world.
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numerical heat transfer analysis of maisotsenko humid air bottoming cycle a study towards the optimization of the air water mixture at bottoming turbine inlet
Applied Thermal Engineering, 2018Co-Authors: Rasikh Tariq, Nadeem Ahmed SheikhAbstract:Abstract Maisotsenko Humid Air Bottoming Cycle (MHABC) is a recently proposed waste heat recovery unit for gas turbine topping cycle. An air saturator is used for the waste heat recovery and air humidification purposes in the bottoming cycle. The humid air is used in bottoming cycle turbine. In this work, detailed heat transfer analysis of the MHABC is proposed along with the evaluation of degree of humidification and energy recovery. The air saturator is numerically simulated after the development of governing ordinary differential equations for the temperature and humidity distribution of the working air. The governing differential equations of air saturator are discretized using first order accurate finite difference scheme and simulated using MATLAB. The results for the air saturator are initially validated using inlet ambient pressure conditions at standard atmospheric conditions. The upper section of the bottoming cycle is modeled using analytical NTU method. The overall performance of the plant with MHABC is also compared with results reported in literature. Temperature and humidity levels for working air is presented. These results show that the proposed MHABC configuration gives maximum work output (58 MW) and efficiency (∼34%) at the air saturator exit relative humidity of 70%. Corresponding to the maximum system output conditions, the dew point effectiveness of the air saturator is noted at 0.8 with 32% relative humidity at the bottoming turbine inlet. While the air split ratio of 50% between lower air saturator and heat exchanger gives more than 8 MW of waste heat recovery.
Mohamed Gadalla - One of the best experts on this subject based on the ideXlab platform.
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analysis of maisotsenko open gas turbine power cycle with a detailed air saturator model
Applied Energy, 2015Co-Authors: Mohammad Saghafifar, Mohamed GadallaAbstract:Abstract With ever increasing cost of fossil fuels and natural gas, the improvement in gas turbine power cycle efficiency is needed due to the tremendous savings in fuel consumption. Water/steam injection is considered as one of the most popular power augmentation techniques because of its significant impact on the gas turbine performance. One of the recently suggested evaporative gas turbine cycles is the Maisotsenko open cycle for gas turbine power generation. In this paper, detailed thermodynamic analysis of this cycle is investigated with a thorough air saturator model. A comparative analysis is carried out to signify the advantages and disadvantages of Maisotsenko gas turbine cycle (MGTC) as compared with humid air gas turbine cycles. MGTC performance is evaluated based on a simple recuperated gas turbine cycle. In addition, sensitivity analysis is performed to investigate the effect of different operating parameters on the overall cycle performance. Finally, integrating an air saturator instead of a conventional heat exchanger in recuperated gas turbine cycles enhances the power plant performance such that an efficiency enhancement of 7% points and net specific work output augmentation of 44.4% are obtained.
Pau Lluis Orts-gonzalez - One of the best experts on this subject based on the ideXlab platform.
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Part-load performance modelling of a reheated humid air turbine power cycle
Applied Thermal Engineering, 2018Co-Authors: Giovanni D. Brighenti, Pavlos K. Zachos, Pau Lluis Orts-gonzalezAbstract:Abstract Humid air turbines have previously demonstrated the potential to deliver high efficiency and power output combined with low emissions. This paper investigates the part-load performance of a 40 MW class advanced humid air turbine for power generation applications across a range of operating conditions. The paper investigates the impact of the main burner and reheater burner on the system’s part-load power output and thermal efficiency and provides insights into the behavior of the key modules across the power spectrum of operation including the saturator tower which was never reported previously. The impact of the ambient air and sea water temperature on the cycle’s performance are also investigated. The outcome of the research shows that the thermal efficiency if the system is less than 0.26% penalized when operating down to 50% of the design power output. Sea water temperature was found to have a more notable impact than ambient air temperature on both power output and thermal efficiency Overall, this work constitutes a step ahead in understanding the potential benefits of an advanced humid air turbine system for power generation applications across a range of operating conditions which is not previously shown.
Shusheng Zang - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on the off design performance of a small sized humid air turbine cycle
Applied Thermal Engineering, 2013Co-Authors: Shusheng ZangAbstract:Abstract This research aimed to study the improvement of the gas turbine performance of a humid air turbine (HAT) cycle at low pressure ratio and at low turbine inlet temperature (TIT). To achieve this goal, an off-design performance test investigation was conducted on a small-sized, two-shaft gas turbine test rig. The test rig consisted of a centrifugal compressor, a centripetal turbine, an individual direct flow flame tube, a free power turbine, a dynamometer, and a saturator with structured packing. Two different conditions were considered for the test investigation: in Case I, the control system kept the fuel flow constant at 57 kg/h, and in Case II, the turbine inlet temperature was kept constant at 665 °C. In Case I, when the air humidity ratio increased from 30 g/kg dry air (DA) to 43 g/kg DA, the power output increased by 3 kW. At the same time, the turbine inlet temperature decreased by 19 °C, and the NOx emissions were reduced from 25 ppm to 16 ppm. In Case II, when the air humidity ratio increased from 48 g/kg DA to 57 g/kg DA, the power output increased by 9.5 kW. Based on the actual gas turbine parts, characteristics, and test conditions, the off-design performance of the HAT cycle was calculated. Upon comparing the measured and calculated results, the HAT cycle was found to perform better than the two-shaft cycle in terms of specific work, efficiency, and specific fuel consumption. The effect of performance improvement became more obvious as the air humidity ratio increased. Under the same inlet air flow, turbine inlet temperature, and power output, the surge margin on compressor curves became enlarged as the humidity ratio increased. The off-design performance of a HAT cycle with regenerator was also investigated. The results show that the highest efficiency can be increased by 3.1%, which will greatly improve the gas turbine performance.
