Gas Turbine Exit Research Articles

Выбор геометрии выходного устройства газотурбинной установки с минималь- ными потерями давления

Object and purpose of research. This paper discusses gas turbine exit unit consisting of axial-radial diffusor and pockettype volute. The purpose of the study was to select the exit unit geometry that would offer minimum losses of total pressure. Subject matter and methods. Experimental results obtained for the models of gas turbine exit units. Calculation of total pressure losses in SolidWorks package with Flow simulation extension. Correction coefficients were obtained through regression analysis. The exit unit geometry offering minimum losses of total pressure was obtained using the theory of experiment planning. Main results. The study yielded correction coefficients to the calculation results obtained in SolidWorks package with Flow simulation extension. Exit unit geometry offering minimum losses of total pressure has been successfully found. The effect of strut location in the radial part of diffusor in terms of pressure losses has been quantified. Conclusion. This study enables early identification of exit unit geometry with minimum total pressure losses, so it is valuable for practical gas turbine design.

Numerical analysis of air entrainment and exit temperature of a real scale conical infrared suppression (IRS) device

A numerical analysis has been performed on a real-scale infrared suppression device to estimate the air entrainment and corresponding temperature drop of the exhaust gases flowing through it. The analysis of the IRS device is done for the exhaust of a gas turbine plant installed on a naval warship. The operational data used in the analysis has been taken from LM2500 series gas turbine from GE. The numerical method solves the three dimensional, incompressible Navier-Stokes equations, the mass continuity equation and the two-equation based eddy viscosity model for the turbulent k-epsilon equations along with the energy equation in the flow field. The effect of using different number of nozzles at the gas turbine exit on the air entrainment and the exit plume temperature has been discussed. The results show that the maximum air entrainment and minimum plume temperature can be achieved by using four to six numbers of nozzles. The air entrainment and the exit plume temperature are also affected by the pitch circle diameter of the nozzle placement. The maximum air entrainment and minimum exit temperature is achieved at a pitch circle diameter of 1.6 m. The air entrainment considerably increases with the nozzle-exit Reynolds number (Re). The higher Reynolds number also ensures the minimum plume temperature at the exit of IRS device. Air entrainment gradually reduces with the nozzle protrusion. The highest entrainment is observed when the nozzles are flush with the bottom plane of the IRS device. However, the nozzle protrusion does not affect the exit plume temperature significantly. The funnel overlap height adversely affects the performance of the IRS device i.e. the air entrainment continuously decreases with increasing funnel overlap height. Moreover, increasing funnel overlap also causes the exit plume temperature to rise considerably.

Optimization of the Process Parameters on the Mechanical and Wear Properties of Al-SiC Nano-Composites Fabricated by Friction Stir Processing Using Desirability Approach

Aluminium silicon carbide (Al-SiC) nano composites find its application in gas turbine exit vane, structural parts of automobile and other structural applications. In the present investigation, optimization of the process parameters on mechanical and wear properties of aluminium SiC nanocomposites fabricated via friction stir processing (FSP) was studied. Three process parameters such as number of passes (A), rotational speed(B) and transverse feed(C) were used. For three factors and three levels, L9 Taguchi method was used to formulate the experimental design. Desirability approach is used to optimize the process parameters in terms of tensile strength, microhardness and wear loss. It is observed that the number of passes is the vital process parameter for tensile strength whereas rotational speed is the vital process parameter for microhardness. For three number of passes, 1500 rpm of rotational speed and 70 mm/min of transverse feed results in optimal process parameter combination for obtaining better values for tensile strength, microhardness and wear loss i.e. A3 B3 C3. The microstructure evaluation for fabricated and worn surfaces was studied using Scanning Electron Microscope (SEM).

Theoretical Study on the Effect of Glycerol Fraction in Slurries with Biomass Consumed by a Power-Generation Process

Previous works have shown that glycerol, which is a residue from biodiesel production, can be applied to greatly increase the efficiency of power generation processes consuming biomass, such as sugar cane bagasse (SCB). The proposed process departs from a biomass and glycerol slurry, which is pumped into a pressurized gasifier. The produced gas is cleaned to reach particle content and sizes as well alkaline concentration allowed to be injected into commercially available axial gas turbines. The removal of alkaline is achieved through cooling the gas to temperatures below the dew-point of those chemical species. Energy recovered from that cooling and from the gas turbine exit, drives two steam cycles. The present theoretical investigation assesses the effects of glycerol concentration in the slurry with wet biomass fed to the process on its overall efficiency. In addition, the gasifier operational pressure is increased to the limit allowed for air compression by axial compressors without intercooling. It s...

Dispersion of Alumina Nano Particles in Al 2219 alloy by Ultrasonic Assisted Stir Casting Technique

Request augments on a worldwide scale for the new materials. The metal matrix nanocomposites can be used in numerous applications of helicopter structural parts, gas turbine exit guide vane’s, space shuttle, and other structural applications. The key mailman to ameliorate performance of composite matrix in aluminium alloy metal reinforces nano particles in the matrix of alloy uniformly, which ameliorates composite ownership without affecting limit of ductility. The ultrasonic assisted stir casting helped agitation was successfully used to fabricate Al 2219 metal matrix of alloy reinforced with (0.5, 1, 1.5 and 2) Wt.% of nano particles Al2O3. The micrographs of scanning electron microscopy of nanocomposite were investigated it reveals that the uniform dispersion of particles of oxide of nano aluminium in Al 2219 matrix of alloy and with the zero porosity. The mechanical properties showed that the ultimate tensile strength and hardness of metal matrix nano composite Al 2219 / nano Al2O3 lean to augment with increase weight percentage of alumina content in the matrix alloy.

Preparation of SiC based Aluminium metal matrix nano composites by high intensity ultrasonic cavitation process and evaluation of mechanical and tribological properties

Request augments on a worldwide scale for the new materials. The metal matrix nano composites can be used in numerous applications of helicopter structural parts, gas turbine exit guide vane's, space shuttle, and other structural applications. The key mailman to ameliorate performance of composite matrix in aluminium alloy metal reinforces nano particles in the matrix of alloy uniformly, which ameliorates composite properties without affecting limit of ductility. The ultrasonic assisted stir casting helped agitation was successfully used to fabricate Al 2219 metal matrix of alloy reinforced with (0.5, 1, 1.5 and 2) wt.% of nano silicon carbide (SiC) particles of different sizes 50nm and 150nm. The micrographs of scanning electron microscopy of nano composite were investigated it reveals that the uniform dispersion of nano particles silicon carbide in aluminium alloy 2219 matrix and with the low porosity. How the specific wear rate was vary with increasing weight percentage of nano particles at constant load and speed as shown in results and discussions. And the mechanical properties showed that the ultimate tensile strength and hardness of metal matrix nano composite AA 2219 / nano SiC of 50nm and 150nm lean to augment with increase weight percentage of silicon carbide content in the matrix alloy.

배열회수보일러 입구 덕트 확관 형상 변화에 따른 전열관군 전단 유동균일화 특성

The present study has been carried out to analyze the flow characteristics in the inlet expasion duct of a heat recovery steam generator by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. Because the flow characteristics in the inlet duct of the tube bank is strongly related to the performance of a HRSG, it is most important for the optimal design of HGSG to understanding the flow phenomena in the inlet duct of HRSG. From the present study, the position of breakpoint in the inlet expansion duct should be lower than the reference breakpoint position for the optimal flow uniformity before the tube bank.

배열회수보일러(HRSG)의 입구유동 경계조건에 따른 유동특성 변화에 관한 연구

본 연구는 배열회수보일러(HRSG)에서의 유동특성을 유동수치해석을 통하여 분석하였다. HRSG 입구영역은 가스터빈 후류의 출구에 해당하고 가스터빈 후류는 강한 선회 및 난류 유동이다. 따라서 HRSG 입구 유동은 가스 터빈 출구 유동 특성이 고려되어야 한다. 본 연구에서는 HRSG 입구 유동 경계조건을 가스터빈 출구 유동 해석을 통하여 도출된 결과를 이용하였다. 가스터빈 출구 유동해석 결과를 보면 축방향 속도가 가장 크게 나타나는 곳이 원형 덕트의 벽면 측이고 난류운동에너지와 소산율이 크게 나타나는 곳이 속도 구배가 급격한 곳으로 축방향 속도가 최대가 되는 곳과 차이가 있다. 본 연구에서는 HRSG 입구영역에서의 난류 성분을 가스터빈 출구 유동을 계산 한 결과를 이용한 경우와 난류강도를 속도의 10%를 이용하고 원형 덕트의 직경을 특성 길이로 사용한 두 가지 경우에 대하여 유동해석을 통하여 유동 특성을 비교하였다. 본 연구를 통하여 HRSG 입구 유동 경계조건은 반드시 난류성분이 올바르게 적용되어야 HRSG 유동 특성 해석의 정확성을 기할 수 있음을 알았다. The present study has been carried out to analyze the flow characteristics of a heat recovery steam generator with the change of inlet flow conditions by using numerical flow analysis. The inlet of HRSG corresponds the outlet of gas turbine exit and the flow after gas turbine has strong swirl flow and turbulence. The inlet flow condition of HRSG should be included the exit flow characteristics of gas turbine. The present numerical analysis adopted the flow analysis result of gas turbine exit flow as a inlet flow condition of HRSG analysis. The computational flow analysis result of gas turbine exit shows that the maximum axial velocity appears near circular duct wall and the maximum turbulent kinetic energy and dissipation rate exist relatively higher gradient region of axial velocity. The comparison of flow analysis will be executed with change of inlet turbulent flow condition. The first case is using the inlet turbulent properties from the result of computational analysis of gas turbine exit flow, and the second case is using the assumed turbulent intensity with the magnitude proportional to the velocity magnitude and length scale. The computational results of flow characteristics for two cases show great difference especially in the velocity field and turbulent properties. The main conclusion of the present study is that the flow inlet condition of HRSG should be included the turbulent properties for the accurate computational result of flow analysis.

Characteristics of transient operation of a dual-pressure bottoming system for the combined cycle power plant

This study simulates the transient behavior of a dual-pressure bottoming system for the combined cycle power plant. In order to set up a comprehensive model to represent the system effectively, unsteady one-dimensional conservation equations for each component are introduced. Controls over water level and turbine power are also incorporated in the simulation process. How the bottoming system responds to the varying conditions of the gas turbine exit was investigated. Two types of the bottoming cycle operation were simulated: a pure sliding-pressure operation (where the shaft power control is not performed) and a modified operation (where the shaft power is controlled to match a given load by modulating the steam flow rate). Variations in the main operating parameters for both low and high pressure levels were examined, and the transient characteristics of two operations were compared.

Analysis of Dynamic Behavior of a Heat Recovery Steam Generator and Steam Turbine System

The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.