Effect Of Compressor Pressure Ratio Research Articles

Thermodynamic investigation of a Carnot battery based multi-energy system with cascaded latent thermal (heat and cold) energy stores

Carnot batteries store electricity in thermal form, allowing for power balancing and also multi-vector energy management as a unique asset. Cascaded thermal energy storage therefore has a vital role in Carnot battery, particularly multi-energy systems delivering electricity and thermal energy at various temperatures. Here, we propose a Carnot battery multi-energy system with cascaded latent thermal energy stores. The effects of compressor pressure ratio, total stage number, stage area and fluid velocity in tubes, on system-level coefficient of performance and total exergy efficiency are investigated. The results show that both the coefficient of performance and exergy efficiency increase significantly and then level off with the total stage number and stage area increasing, while they only increase slightly before a significant decrease with the increase of fluid velocity in tubes. The selection of compressor pressure ratios relates to the demands of cold, heat and electricity. The multi-energy system achieves a maximum coefficient of performance of 95.0% in combined cooling, heating and power mode. Although the thermodynamic performance yileds comparable with Carnot battery systems integrated with packed-bed or liquid-based sensible heat stores, the Carnot battery multi-energy system can deliver electricity and multi-grade heat and cold simultaneously, thus increasing flexibility in future energy systems.

Energy/power efficiency and parametric optimisation of a non-afterburning turbojet engine

In this study, the fluid power values per unit mass flow in a turbojet engine were calculated under different design criteria at on-design phase. Emphasis is placed on understanding and applying the effect of compressor pressure ratio (πc) and turbine inlet temperature (TIT) on the fluid specific total power (TPs), specific wasted power (WPs), specific thrust power (τPs), specific fuel consumption and overall efficiency. Also, these design parameters (πc and TIT) are optimised with genetic algorithm for better system efficiency. The analysis results obtained via on-design method are quantified for 3 ≤ πc ≤ 10, 1,000 K ≤ TIT ≤ 1,400 K. According to the results of optimisation for minimum specific fuel consumption, optimum values of WPs and τPs are found 156.384 kJ/kg and 133.953 kJ/kg, respectively. Optimum propulsive, thermal and overall efficiencies which are performance parameters are determined 48.5%, 37.04% and 17.96% respectively.

Thermodynamic analysis of a supercritical closed Brayton cycle integrated with parabolic trough solar collectors

In this study, thermodynamic analysis of a supercritical closed Brayton cycle integrated with parabolic trough solar collectors operating with various organic-based working fluid types is conducted. To examine the performance of this integrated system, a mathematical model, including the energy and exergy analyses of the system, is first developed; after that, a parametric study is performed to determine the effect of compressor pressure ratio, solar irradiation, and type of working fluid on the system performance. In addition, a case study, in which the integrated system is analyzed with the meteorological data of Alasehir, Manisa, Turkey, is conducted in order to assess its monthly performance. The results indicate that when the working fluid is taken as R744 (CO2), the performance of the system gets better compared to that based on other types of working fluids. On the other hand, the case study illustrates that the highest and lowest annual electricity generations are calculated as 7.89 GWh and 2.18 GWh for R245fa and R23, respectively. In addition, the highest and lowest yearly water consumptions in the cooling tower are found as 6680 tonnes and 5870 tonnes for R23 and R245fa, respectively.

Exergy and exergoeconomic analyses of a novel integration of a 1000 MW pressurized water reactor power plant and a gas turbine cycle through a superheater

Combined cycles are used for various reasons, including to increase the efficiency of power generation system. In this study, a gas turbine cycle is combined with a pressurized water reactor (PWR) power plant to increase the total plant efficiency. In this novel cycle, saturated steam produced in the steam generators of the nuclear power plant is superheated by the hot combustion gases exiting the gas turbine. An exergoeconomic analysis is carried out and the effects of compressor pressure ratio and gas turbine inlet temperature are investigated on the net power output, the first and second law efficiencies, the total cost rate and the specific cost of the produced work. The results show that there is an optimum pressure ratio for each gas turbine inlet temperature. The combined cycle total cost rate and the specific cost of the produced work for a gas turbine inlet temperature of 1500 K and a compressor pressure ratio of 13 are determined to be 41,882 $/h and 31.63 $/MWh, respectively.

Thermodynamic assessment of advanced SOFC-blade cooled gas turbine hybrid cycle

This paper focuses on novel integration of high temperature solid oxide fuel cell coupled with recuperative gas turbine (with air-film cooling of blades) based hybrid power plant (SOFC-blade cooled GT). For realistic analysis of gas turbine cycle air-film blade cooling technique has been adopted. First law thermodynamic analysis investigating the combine effect of film cooling of blades, SOFC, applied to a recuperated gas turbine cycle has been reported. Thermodynamic modeling for the proposed cycle has been presented. Results highlight the influence of film cooling of blades and operating parameters of SOFC on various performance of SOFC-blade cooled GT based hybrid power plant. Moreover, parametric investigation has also been done to examine the effect of compressor pressure ratio, turbine inlet temperature, on hybrid plant efficiency and plant specific work. It has been found that on increasing turbine inlet temperature (TIT) beyond a certain limit, the efficiency of gas turbine starts declining after reaching an optimum value which is compensated by continuous increase in SOFC efficiency with increase in operating temperature. The net result is higher performance of hybrid cycle with increase in maximum cycle temperature. Furthermore, it has been observed that at TIT 1600 K and compression ratio 20, maximum efficiency of 73.46% can been achieved.

Energy-exergy analysis of compressor pressure ratio effects on thermodynamic performance of ammonia water combined cycle

The purpose of this study is to investigate the effect of compressor pressure ratio (RP) on the thermodynamic performances of ammonia-water combined cycle through energy and exergy destruction, enthalpy temperature, yields, and flow velocity. The energy-exergy analysis is conducted on the ammonia water combined cycle and the Rankine cycle, respectively. Engineering Equation Solver (EES) software is utilized to perform the detailed analyses. Values and ratios regarding heat drop and exergy loss are presented in separate tables for different equipments. The results obtained by the energy-exergy analysis indicate that by increasing the pressure ratio compressor, exergy destruction of high-pressure compressors, intercooler, gas turbine and the special produced work of gas turbine cycle constantly increase and the exergy destruction of recuperator, in contrast,decreases continuously. In addition, the least amount of input fuel into the combined cycleis observed when the pressure ratio is no less than 7.5. Subsequently, the efficiency of the cycle in gas turbine and combined cycle is reduced because the fuel input into the combined cycle is increased.

Analysis of Combined Effects of Air Transpiration Cooling and Evaporative Inlet Air Cooling on the Performance Parameters of a Simple Gas Turbine Cycle

This paper is focused on accessing the benefits of incorporating an air humidifier with a cooled gas turbine cycle. Air transpiration cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor pressure ratio (rp,c), compressor inlet temperature (CIT), turbine inlet temperature (TIT), inlet temperature ratio (rIT), ambient relative humidity, and ambient temperature on performance parameters of plant has been carried out. Evaporative inlet air cooling has been observed to improve the plant efficiency of a transpiration cooled gas turbine plant by 4.84% and plant specific work by 9.68% at an ambient temperature of 313 K and ambient relative humidity of 0.2. The effects of variation of ambient parameters on cycle performance are found to be more pronounced at higher turbine inlet temperature and higher compression ratio (rp,c). The work ratio increases with an increase in the value of rIT up to 5.6 after which it decreases. There exists an optimum rIT at any rp,c with reference to the maximum work ratio. The heat rate increases with an increase in rIT and a decrease in rp,c. For all values of TIT there exists an optimum rp,c at which plant efficiency is at its maximum.

Thermodynamic assessment of impact of inlet air cooling techniques on gas turbine and combined cycle performance

The article is focused on the comparison of impact of two different methods of inlet air cooling (vapor compression and vapor absorption cooling) integrated to a cooled gas turbine based combined cycle plant. Air-film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor pressure ratio, compressor inlet temperature (Ti,C), turbine inlet temperature (Ti,T), ambient relative humidity and ambient temperature on performance parameters of plant has been carried out. Optimum Ti,T corresponding to maximum plant efficiency of combined cycle increases by 100 °C due to the integration of inlet air cooling. It has been observed that vapor compression cooling improves the efficiency of gas turbine cycle by 4.88% and work output by 14.77%. In case of vapor absorption cooling an improvement of 17.2% in gas cycle work output and 9.47% in gas cycle efficiency has been observed. For combined cycle configuration, however, vapor compression cooling should be preferred over absorption cooling in terms of higher plant performance. The optimum value of compressor inlet temperature has been observed to be 20 °C for the chosen set of conditions for both the inlet air cooling schemes.

Performance analysis of an air humidifier integrated gas turbine with film air cooling of turbine blade

A computational analysis to investigate the effects of compressor pressure ratio, turbine inlet temperature, ambient relative humidity and ambient temperature on the performance parameters of an air cooled gas turbine cycle with evaporative cooling of inlet air has been presented. The blade cooling method selected is film cooling. The analysis indicates that the mass of coolant required for blade cooling is reduced with increase in temperature drop across the humidifier. Both decrease in ambient temperature and ambient relative humidity results in an increase in plant efficiency and plant specific work. The highest efficiency is obtained at a turbine inlet temperature of 1500 K for all range of ambient relative humidity and ambient temperature, beyond which it decreases. The compressor pressure ratio corresponding to the maximum plant specific work, however, varies with both ambient relative humidity and ambient temperature. The increase in specific work due to drop in ambient relative humidity is more pronounced at higher pressure ratios. Similarly, the increase in efficiency due to ambient temperature drop is prominent at higher turbine inlet temperatures. Finally, a design nomograph is presented to select the design parameters corresponding to best efficiency and specific work.

Analytical Investigation of Parameters Affecting the Performance of Cooled Gas Turbine Cycle with Evaporative Cooling of Inlet Air

The article investigates the effect of compressor pressure ratio, turbine inlet temperature, ambient relative humidity and ambient temperature on the performance parameters of an air-cooled gas turbine cycle with evaporative cooling of inlet air. Air-film cooling has been adopted as the cooling technique for gas turbine blades. The mass of coolant required for turbine blade cooling is calculated for a selected range of ambient conditions and found to vary with temperature drop achieved in the evaporator. The effect of ambient temperature and ambient relative humidity on plant efficiency and plant-specific work is computed at different TIT and r p,c and it was found that the rate of increase in these performance parameters are more pronounced at higher TIT and r p,c. The results indicate that a maximum temperature drop of 21 °C is achieved in the evaporator. The inlet cooling is found to increase the efficiency by 4.1% and specific work by 9.44 %.

Thermodynamic analysis of the effect of blade cooling methods on air humidifier integrated gas turbine cycle

The paper investigates the effect of compressor pressure ratio, turbine inlet temperature, ambient relative humidity (RH) and ambient temperature on the performance parameters of a gas turbine cycle with evaporative cooling of inlet air and different means of blade cooling. The cooling techniques include film, transpiration and internal convection cooling (ICC). The mass of coolant required for turbine blade cooling is found to decrease with a decrease in ambient temperature and ambient RH. The coolant mass required for turbine blade cooling is lowest for transpiration cooling (TC) followed by film and ICC. However, the highest reduction in coolant mass and the highest enhancement in plant efficiency and work (due to the decrease in ambient RH and ambient temperature) are observed in case of ICC followed by film cooling and TC. The increase in performance parameters due to the addition of inlet cooling system is also found to be maximum for ICC. The inlet cooling improves the plant efficiency by 11·3% and...

Gaz Türbinlerinin Optimal Performans Analizi

The usage of gas turbines increases rapidly in the electricity production and cogeneration systems in recent years. Decreasing performance of gas turbines causes not only reducing their capacity of electricity production but also increasing production cost. In this study, the thermodynamic analysis of the open cycle gas turbine model is examined. The power output and the thermal efficiency of system are chosen as the performance criteria and the effects of compressor pressure ratio, turbine inlet temperature, isentropic efficiencies and pressure losses on the performance are analyzed. Developed model has been solved by using the computer program written in Visual Basic language and the design parameters giving maximum power and efficiency are determined.