The part-load performance of a gas turbine engine with two turbines working in parallel (original) (raw)
Comparison between two gas turbine solutions to increase combined power plant efficiency
Energy Conversion and Management, 2000
Signi®cant research eorts are currently centered on developing advanced gas turbine systems for electric power generation applications. Gas±steam combined cycles are often used to obtain a high eciency power plant. Two innovative gas turbine technologies have recently been proposed for combined cycle applications. Two gas±steam combined cycles using thermodynamic analysis are presented: a combined cycle with three pressure levels with reheat heat recovery boiler is used with two dierent gas turbine technologies (high pressure ratio and reheat against``H'' technology). This analysis constitutes a comparison not only between two dierent constructive solutions but also between two dierent gas turbine (GT) techniques (reheat and GT steam cooling) and technologies (a consolidated and an advanced gas turbine technology) applied to a combined cycle.
Stationary gas turbines: an exergetic approach to part load operation
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2020
As renewables are progressively displacing thermal plants in the power generation scene worldwide, the vocation of stationary Gas Turbines (GT) is deeply evolving. In this irreversible move GT plants are called upon to become cycling units with increasingly variable load profiles. This is dictated by the need to compensate for the fluctuations of renewable energy sources and secure the spinning reserve that is indispensable for the stability of the grids. This new scenario creates a serious challenge for gas turbine designers and operators in terms of investment policy, plant management and equipment lifetime. Indeed, operating a gas turbine at part, variable load requires reducing its firing temperature and possibly its air flow. While part load operation entails efficiency losses with respect to the full load mode, load variations cause maintenance penalties due the premature component ageing tied namely with thermal and low cycle fatigue effects on machine materials. As far as efficiency is concerned, an exergy analysis of a contemporary, air-based Brayton cycle is useful for quantifying and comparing the losses incurred by the various engine components. Such study reveals the high sensitivity of compressor efficiency to load decreases. Among possible countermeasures , heating the air at the compressor intake represents a simple mitigation measure, as it enables reducing the air flow rate while preserving to some extent the efficiency of the compressor and consequently GT efficiency.
Thermodynamic Analysis of Gas Turbine
2012
This project is intended to do analysis of a gas turbine engine performance. The gas turbine operating conditions (pressure ratio, turbine inlet and exhaust temperatures, fuel to air ratio, isentropic compressor and turbine efficiencies and ambient temperature) affect the turbine performance. The performance indicators are thermal efficiency, compressor work, power output, specific fuel consumption and heat rate. This project will focus on the effect of ambient temperature, turbine inlet temperature, air to fuel ratio and compression ratio on the efficiency and output power of the turbine. The gas turbine basic components were modelled based on thermodynamics principle. The developed components models were integrated using conservation of mass and energy balance. In
Thermodynamics Performance Evaluation of a Two-Shaft Gas Turbine Power Plant
2014
In this work, the performance of a two-shaft Gas Turbine power plant was evaluated based on the efficiencies of the plant from the year 2002 to 2007.The parameters used in the evaluation are the ambient conditions, thermal efficiencies, and the inlet and outlet temperatures of the power turbine. The results showed that the highest thermal efficiency of the turbine was obtained in the year 2006 when the average compressor inlet temperature of the turbine and the power turbine outlet (exhaust) temperature are the least. With the increase in thermal efficiency of 42.62%, rise in value of compressor pressure ratio of 7.78 and least compressor inlet temperature of 25.08 0 C as seen in table 2. The research shows that gas turbine plants perform better in temperate regions than tropical. Therefore, to increase the efficiency of an existing gas turbine plants in high temperature climates, retrofitting an air cooler that will always reduce the temperature back or close to the design temperat...
DEVELOPMENT AND VALIDATION OF A TWIN SHAFT INDUSTRIAL GAS TURBINE PERFORMANCE MODEL
Gas turbine performance is very responsive to ambient and operational conditions. If the engine is not operating at its optimum conditions, there will be high energy consumption and environmental pollution. Hence, a precise simulation model of a gas turbine is needed for performance evaluation and fault detection and diagnostics. This paper presents a twin shaft industrial gas turbine modeling and validation. To develop the simulation model component maps are important, however they are property of the manufacturers and classified documents. In this case, known the compressor pressure ratio, speed, and flow rate, the missing design parameters, namely turbines inlet temperatures and pressure ratios were predicted using GasTurb simulation software. Once the design parameters are developed, the nearest compressor and turbine maps were selected from GasTurb map collection. Beta lines were introduced on each map so that the exact corresponding value can be picked for a given two parameters of a given map. After the completion of components model, a simulation model was developed in Matlab environment. The equations governing the operation of individual component were solved using iteration method. The simulation model has modular nature; it can be modified easily when a change is required. The parameters that the model can predict include terminal temperature and pressure, flow rate, specific fuel consumption, thermal efficiency and heat ratio. To demonstrate the validity of the developed model, the performance of GE LM2500 twin shaft gas turbine operating in a gas oil industry at Resak PETRONAS platform in Malaysia was predicted and compared with operational data. The results showed that an average of 5, 3.8 and 3.7 % discrepancies for compressor discharge temperature and pressure, and fuel flow rate, respectively. This comparison of results showed good agreement between the measured and predicted parameters. Thus, the developed model can be helpful in performance evaluation of twin shaft gas turbines and generation of data for training and validation of a fault detection and diagnostic model.
SCIENTIFIC RESEARCH AND EDUCATION IN THE AIR FORCE
When we read the technical data of any kind of gas turbine engines in most cases besides the performance data we get two important data, namely the Turbine Inlet Temperature (TIT) and Compressor Pressure Ratio (CPR) usually for takeoff rate of power. But considering a certain TIT there is a range of CPR which is suitable for this TIT. This range of CPR depends on the TIT itself but the engine component efficiencies also has effect on the possible CPR. In this paper we intended to examine how this range of CPR can be determined, the range itself, how it is affected by the component efficiencies and the operational point of today existing turboshaft engines between the minimum and maximum possible CPR-s. To answer these questions we developed a gas turbine thermal mathematical model.
Thermodynamic performance analysis of gas-turbine power-plant
2011
This paper was presented the parametric study of thermodynamic performance on gas turbine power plant. The variation of operating conditions (compression ratio, turbine inlet and exhaust temperature, air to fuel ratio, isentropic compressor and turbine efficiency, and ambient temperature) on the performance of gas turbine (thermal efficiency, compressor work, power, specific fuel consumption, heat rate) were investigated. The analytical formula for the specific work and efficiency were derived and analyzed. The programming of performance model for gas turbine was developed utilizing the MATLAB software. The results show that the compression ratio, ambient temperature, air to fuel ratio as well as the isentropic efficiencies are strongly influence on the thermal efficiency. In addition, the thermal efficiency and power output decreases linearly with increase of the ambient temperature and air to fuel ratio. However, the specific fuel consumption and heat rate increases linearly with increase of both ambient temperature and air to fuel ratio. Thus the thermodynamic parameters on cycle performance are economically feasible and beneficial for the gas turbine operations.
Study of two-stage turbine characteristic and its influence on turbo-compound engine performance
Turbo-compounding is an effective way to recover waste heat from engine exhaust and reduce fuel consumption for internal combustion engine (ICE). The characteristics of two-stage turbine, including tur-bocharger turbine and power turbine, have significant effects on the overall performance of turbo-compound engine. This paper investigates the interaction between two turbines in a turbo-compound engine and its impact on the engine performance. Firstly an analytical model is built to investigate the effects of turbine equivalent flow area on the two-stage turbine characteristics, including swallowing capacity and load split. Next both simulation and experimental method are carried out to study the effects of high pressure variable geometry turbine (HP VGT), low pressure variable geometry turbine (LP VGT) and combined VGT on the engine overall performance. The results show that the engine performance is more sensitive to HP VGT compared with LP VGT at all the operation conditions, which is caused by the larger influences of HP VGT on the total expansion ratio and engine air–fuel ratio. Using the HP VGT method, the fuel reductions of the turbo-compound engine at 1900 rpm and 1000 rpm are 3.08% and 7.83% respectively, in comparison with the baseline engine. The corresponding optimum values of AR are 2.0 and 2.5.
Performance Investigation of Combined Cycle Gas Turbine under Varying Operating Conditions
2017
Combined Cycle Gas Turbine is used to achieve higher thermal efficiency and utilisation of energy efficiently by minimizing the energy loss. Gas Turbine as topping cycle integrated with steam turbine as bottoming cycle is generally named as combined cycle gas turbine (CCGT). In this paper, the performance of the CCGT is investigated thermodynamically using MATLAB coding technique under varying operating parameters such as Compression Pressure ratio, Compressor inlet temperature, Turbine inlet temperature and Air Fuel ratio. The extreme overall efficiency occurs at the higher compression pressure ratio with low compressor inlet temperature and higher turbine inlet temperature, while, the overall thermal efficiencies for CCGT are higher compared to the individual thermal efficiencies of the gas turbine and steam turbine power plants. The total power output raise with an increase of cycle peak temperature ratio and decrease of the compression pressure ratio.