scholarly journals Ignition and Flame Stabilization of a Strut-Jet RBCC Combustor with Small Rocket Exhaust

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Jichao Hu ◽  
Juntao Chang ◽  
Wen Bao
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flame Stabilization ◽  
Combined Cycle ◽  
Pure Oxygen ◽  
Pilot Method ◽  
Total Temperature ◽  
Series Of Experiments ◽  
Rocket Exhaust

A Rocket Based Combined Cycle combustor model is tested at a ground direct connected rig to investigate the flame holding characteristics with a small rocket exhaust using liquid kerosene. The total temperature and the Mach number of the vitiated air flow, at exit of the nozzle are 1505 K and 2.6, respectively. The rocket base is embedded in a fuel injecting strut and mounted in the center of the combustor. The wall of the combustor is flush, without any reward step or cavity, so the strut-jet is used to make sure of the flame stabilization of the second combustion. Mass flow rate of the kerosene and oxygen injected into the rocket is set to be a small value, below 10% of the total fuel when the equivalence ratio of the second combustion is 1. The experiment has generated two different kinds of rocket exhaust: fuel rich and pure oxygen. Experiment result has shown that, with a relative small total mass flow rate of the rocket, the fuel rich rocket plume is not suitable for ignition and flame stabilization, while an oxygen plume condition is suitable. Then the paper conducts a series of experiments to investigate the combustion characteristics under this oxygen pilot method and found that the flame stabilization characteristics are different at different combustion modes.

Cylindrical Parabolic Trough Concentrator and Solar Tower Comparison in an Integrated Solar Combined Cycle Power Plant

2019 ◽  
Author(s):  
Héctor J. Bravo ◽  
José C. Ramos ◽  
César Celis
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Combined Cycle ◽  
Parabolic Trough ◽  
Combined Cycle Power Plant ◽  
Design Point ◽  
Concentrated Solar Energy

Abstract The intermittency of renewable energies continues to be a limitation for their more widespread application because their large-scale storage is not yet practical. Concentrating solar power (CSP) has the possibility of thermally storing this energy to be used in times of higher demand at a more feasible storage price. The number of concentrated solar energy related projects have grown rapidly in recent years due to the advances in the associated solar technology. Some of the remaining issues regarding the associated high investment costs can be solved by integrating the solar potential into fossil fuel generation plants. An integrated solar combined cycle system (ISCCS) tends to be less dependent to climatic conditions and needs less capital inversion than a CSP system, letting the plant be more reliable and more economically feasible. In this work thus, two technologies of solar concentration (i) parabolic trough cylinder (PTC) and (ii) solar tower (ST) are initially integrated into a three-pressure levels combined cycle power plant. The proposed models are then modeled, simulated and properly assessed. Design and off design point computations are carried out taking into account local environmental conditions such as ambient temperature and direct solar radiation (DNI). The 8760 hourly-basis simulations carried out allow comparing the thermal and economic performance of the different power plant configurations accounted for in this work. The results show that injecting energy into the cycle at high temperatures does not necessarily imply a high power plant performance. In the studied plant configurations, introducing the solar generated steam mass flow rate at the evaporator outlet is slightly more efficient than introducing it at cycle points where temperatures are higher. At design point conditions thus, the plant configuration where the referred steam mass flow rate is introduced at the evaporator outlet generates 0.42% more power than those in which the steam is injected at higher cycle temperatures. At off design point conditions this value is reduced to 0.37%. The results also show that the months with high DNI values and those with low mean ambient temperatures are not necessarily the months which lead to the highest power outputs. In fact a balance between these two parameters, DNI and ambient temperature, leads to an operating condition where the power output is the highest. All plant configurations analyzed here are economically feasible, even so PTC related technologies tend to be more economically feasible than ST ones due to their lower investment costs.

Absorption Process in MgCl2–NH3 Thermochemical Batteries With Constant Mass Flow Rate

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Seyyed Ali Hedayat Mofidi ◽  
Kent S. Udell
Keyword(s):  
Mass Transfer ◽  
Mass Flow Rate ◽  
Reaction Zone ◽  
Mass Flow ◽  
Flow Rate ◽  
Absorption Rate ◽  
Constant Mass ◽  
Absorption Process ◽  
Cell Reactor ◽  
Series Of Experiments

In this paper, the performance of a thermochemical battery based on magnesium chloride and ammonia pair with a constant mass flow rate of ammonia gas is studied through a series of experiments using single and multicell configurations. It is shown that a lower mass flow rate lowers the temperature of the reactive complex and increases the duration of the absorption process. However, it was observed that the reaction eventually becomes mass transfer limited which slows the absorption rate to values below those specified by the mass flow controller (MFC). It was shown in the single-cell reactor that a reaction zone starts at the inlet and moves toward the end of the reactor. The mass transfer limited reaction zone movement reduces the absorption rate and temperature in the reaction zone. The overall performance of a multicell thermal battery is also studied to analyze behavior of such reactors as well. It was shown that the controlling the flow rate of ammonia can cause the cells to deviate in absorption rate.

The Study of the Effects of Gas Turbine Inlet Air Cooling on the Heat Recovery Boiler Performance

Volume 1 ◽  
2004 ◽  
Author(s):  
Mohammad Ameri ◽  
Hamidreza Shahbaziyan ◽  
Hadi Hosseinzadeh
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flue Gas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Cooling System ◽  
Combined Cycle ◽  
Heat Recovery Boiler ◽  
Air Cooling

Heat recovery steam generators (HRSG) are widely used in industrial processes and combined cycle power plants. The quantity and the state of the produced steam depend on the flue gas temperature and its mass flow rate. Two key factors, which affect those parameters, are the ambient temperature and the load of the gas turbines. The output power of the gas turbines degrades considerably in hot days of summer. The use of the inlet air cooling system to eliminate this problem is rapidly increasing. One of the effective methods is cooling the inlet air to the compressor by Evaporative Coolers. The purpose of this paper is to study the effects of the evaporative inlet air cooling system on the performance of a heat recovery boiler in a combined cycle power plant. The heat and mass balance of a typical HRSG and its components including the superheaters, evaporators and economizers were calculated. To analyze the effects of the changes in ambient temperature and the flue gas flow, a numerical software has been used. The results have shown that using the evaporative cooler will increase the flue gas mass flow rate to the HRSG. Nevertheless, the exhaust gas temperature control system holds this temperature almost constant. Also, the results show that the produced steam temperature remains almost constant. However, the steam mass flow rate increases. Therefore the output power of the steam turbine of the combined cycle will increase. The effect of the increase in the humidity ratio is shown to be insignificant. In fact, it has negligible effect on the produced steam flow rate and the sulfuric acid dew point.

Analysis of Off-Design Behavior of a Solar-Fossil Hybrid Combined Cycle Plant Using a Small Particle Heat Exchange Receiver (SPHER) With a Variable Guide Vane Gas Turbine

2016 ◽  
Author(s):  
Matthew Miguel Virgen ◽  
Fletcher Miller
Keyword(s):  
Heat Exchange ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Small Particle ◽  
Guide Vane ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Inlet Temperature

Two significant goals in solar plant operation are lower cost and higher efficiencies. This is both for general competitiveness of solar technology in the energy industry, and also to meet the US DOE Sunshot Initiative Concentrating Solar Power (CSP) cost goals [1]. We present here an investigation on the effects of adding a bottoming steam power cycle to a solar-fossil hybrid CSP plant based on a Small Particle Heat Exchange Receiver (SPHER) driving a gas turbine as the primary cycle. Due to the high operating temperature of the SPHER being considered (over 1000 Celsius), the exhaust air from the primary Brayton cycle still contains a tremendous amount of exergy. This exergy of the gas flow can be captured in a heat recovery steam generator (HRSG), to generate superheated steam and run a bottoming Rankine cycle, in a combined cycle gas turbine (CCGT) system. A wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP CCGT plant. Due to the generalized nature of the bottoming cycle modeling, and the varying nature of solar power, special consideration had to be given to the behavior of the heat exchanger and Rankine cycle in off-design scenarios. Variable guide vanes (VGVs), which can control the mass flow rate through the gas turbine system, have been found to be an effective tool in providing operational flexibility to address the variable nature of solar input. The effect VGVs and the operating range associated with them are presented. Strategies for meeting a minimum solar share are also explored. Trends with respect to the change in variable guide vane angle are discussed, as well as the response of the HRSG and bottoming Rankine cycle in response to changes in the gas mass flow rate and temperature. System efficiencies in the range of 50% were found to result from this plant configuration. However, a combustor inlet temperature (CIT) limit lower than a turbine inlet temperature (TIT) limit leads two distinct Modes of operation, with a sharp drop in both plant efficiency and power occurring when the air flow through the receiver exceeded the (CIT) limit, and as a result would have to bypass the combustor entirely and enter the turbine at a significantly lower temperature than nominal. Until that limit is completely eliminated through material or design improvements, this drawback can be addressed through strategic use of the variable guide vanes. Optimal operational strategy is ultimately decided by economics, plant objectives, or other market incentives.

scholarly journals Estimation of condensate mass flow rate during purging time in heat recovery steam generator of combined cycle power plant

2014 ◽  
Vol 18 (4) ◽  
pp. 1389-1397 ◽  
Author(s):  
M.A. Ehyaei
Keyword(s):  
Mass Flow Rate ◽  
Steam Generator ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Recovery ◽  
Steam Pressure ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Gas Temperature ◽  
Condensate Formation

In this paper the transient modeling of HRSG (Heat recovery steam generator) in purging time was considered. In purging time, compressed air from the gas turbine was used to purge a combustible gas from HRSG. During this time; steam condensate was formed in the superheater stage which should be drained completely to avoid some problems such as deformation of superheaters. Because of this reason, estimation of drain formation is essential to avoid this problem. In this paper an energy model was provided and this model was solved by MATLsoftware. Average model error is about 5%. Results show that, during purge time, steam temperature was decreased from 502 (?C) (Superheater 2), 392 (?C) (Superheater1) and 266 (?C) (Evaporators 1&2) to 130 (?C), 130 (?C) and 220 (?C), respectively and also steam pressure was decreased from 52 (bar) to 23(bar) during purge time. At end of purge time, condensate formation was about 220 (l) when inlet gas temperature was equal to 100 (?C) and purge gas mass flow rate was equal to 386.86 (kg/s).

scholarly journals Air Bag Momentum Force Including Aspiration

1995 ◽  
Vol 2 (2) ◽  
pp. 99-109
Author(s):  
Guy Nusholtz ◽  
Deguan Wang ◽  
E. Benjamin Wylie
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Sampling Procedure ◽  
Gas Jet ◽  
Cfd Model ◽  
System A ◽  
Jet Behavior ◽  
Series Of Experiments ◽  
Air Bag

A gas-jet momentum force drives the air bag into position during a crash. The magnitude of this force can change as a result of aspiration. To determine the potential magnitude of the effect on the momentum force and mass flow rate in an aspirated system, a series of experiments and simulations of those experiments was conducted. The simulation consists of a two-dimensional unsteady isentropic CFD model with special “infinite boundaries”. One of the difficulties in simulating the gas-jet behavior is determining the mass flow rate. To improve the reliability of the mass flow rate input to the simulation, a sampling procedure involving multiple tests was used, and an average of the tests was adopted.

Theoretical and Numerical Analysis on the Temperature Drop and Power Consumption of a Pre-Swirl System

2016 ◽  
Author(s):  
Gaowen Liu ◽  
Heng Wu ◽  
Qing Feng ◽  
Songling Liu
Keyword(s):  
Theoretical Analysis ◽  
Power Consumption ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Temperature Drop ◽  
Cover Plate ◽  
Radial Location ◽  
Total Temperature ◽  
Cooling Air

As a component of delivering cooling air to turbine rotor blade at appropriate pressure, temperature and mass flow rate, pre-swirl system is very important to the cooling of turbine blades. It is attractive to the designers and scholars for its potential ability to reduce relative total temperature of cooling air as large as 100K. A pre-swirl system is actually an aero-thermodynamic system with energy transformation between work and heat. Theoretical analysis was carried out on an isentropic pre-swirl system to deduce equations for ideal temperature drop and power consumption. For an actual pre-swirl system, correlation between the actual temperature drop and power consumption was deduced, and a temperature drop effectiveness was defined also. Theoretical analysis shows that the system’s temperature drop increases linearly with the reduction of the power consumption. Numerical models were derived from a real engine pre-swirl system with small simplification. Standard k-ε turbulence model and Frozen-Rotor approach were applied in the three dimensional steady simulations. Inlet total pressure and total temperature, outlet static pressure, mass flow rate delivered to the blade and rotating speed of rotor were kept to be fixed for all the models. The influences of heat transfer and sealing flow coming from the inner seal were ignored in the simulations. Section averaged parameters like pressure, swirl ratio and total enthalpy were presented at each typical station throughout the flow path. The relationship between the temperature drop and the power consumption of all the models has been verified to be consistent with the deduced formula. For the pre-swirl system with low radial location of nozzle, these measures, such as adding impellers in the cover-plate cavity and inclining the receiver hole, were taken to reduce the power consumption and enlarge the temperature drop obviously. For this specific pre-swirl system, models with high radial location of nozzle are more recommended to decrease the loss caused by the large circumferential velocity difference between the airflow and the rotor.

Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet for TBCC

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yunfei Wang ◽  
Huacheng Yuan ◽  
Jinsheng Zhang ◽  
Zhenggui Zhou
Keyword(s):  
Mach Number ◽  
Performance Analysis ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Design Method ◽  
Aerodynamic Performance ◽  
Combined Cycle ◽  
Variable Geometry

Abstract Design and aerodynamic performance analysis of a variable geometry axisymmetric inlet was carried out for tandem scheme turbine-based combined cycle (TBCC) propulsion system. The operation Mach number of the inlet was between 0 and 4. The design point was chosen as Mach number 4.0 in this paper. The determination of external and internal compression and the design method of annular to circle diffuser were illustrated. The inlet was unstart under Ma 3.0 without adjustment. Then, a variable scheme was designed to ensure self-start of the inlet and match the requirement of mass flow rate during the whole flight envelope. And four supports were used to fix the spike. According to the 3D numerical simulations, the total pressure recovery was 0.52 at Ma 4.0 at critical condition and the mass flow rate was consistent with the requirement at different flight Mach number.

Modeling the Performance Characteristics of Diesel Engine Based Combined-Cycle Power Plants—Part II: Results and Applications

2004 ◽  
Vol 126 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Stan N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Diesel Engine ◽  
Power Plant ◽  
Steam Turbine ◽  
Fuel Consumption ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Combined Cycle ◽  
Performance Characteristics ◽  
Combined Cycle Power Plant

In this two-part series publication a mathematical model of the energy conversion process in a diesel engine based combined-cycle power plant has been developed and verified. The examined configuration consists of a turbocharged diesel engine (the topping cycle), a heat recovery steam generator (HRSG) and a steam turbine plant (the bottoming cycle). The model is then used to provide an analysis of performance characteristics of the combined-cycle power plant for steady-state operation. Numerous practical performance parameters of interest have been generated, such as the mean indicated pressure, specific fuel consumption, hourly fuel consumption, brake horsepower of diesel engine, mass flow rate, pressure, and temperature of gases and air, respectively, through the gas turbine and compressor (in the frame of a turbocharger), temperature of flue gases at boiler inlet and outlet, mass flow rate of exhaust gases through the convection coils, and mass flow rate, temperature, pressure, and enthalpy of superheated steam. The performance maps have been derived. The effect of change in the major operating variables (mutual operation of diesel engine, HRSG, and steam turbine) has been analyzed over a range of operating conditions, including the engine load and speed. The model is used as a desktop design tool for accurate predictions of cycle performance, as well as insight into design trends.

Sign in / Sign up

Export Citation Format

Share Document