Reduction of Gaseous Emission From Turbine Combustor

2005 ◽  
Author(s):  
R. S. Amano ◽  
J. Xie ◽  
Shyam Singh ◽  
R. E. Peck
Keyword(s):  
Heat Transfer ◽  
Porous Layer ◽  
Operating Conditions ◽  
Ceramic Foam ◽  
Spray Combustion ◽  
Hydrocarbon Emissions ◽  
Flame Zone ◽  
Enhanced Heat Transfer ◽  
Firing Rates ◽  
Unburned Hydrocarbon

A study of spray combustion with porous inserts was performed using an on-axis fuel used in a concentric Jet-A. Combustion performance was evaluated by measuring exhaust emissions and gaseous temperatures for different operating conditions with and without ceramic foam inserts. The results indicated that the enhanced heat transfer in the flame zone could reduce nitrogen oxides and unburned hydrocarbon emissions. Placing a second porous layer downstream could yield further reductions in both emissions. The results for different firing rates and equivalence ratios revealed the residence time in the porous layer is an important factor in controlling the combustor performance.

Simulation of Gas Turbine Reacting Flows

2005 ◽  
Author(s):  
R. S. Amano ◽  
J. Xie
Keyword(s):  
Porous Layer ◽  
Reacting Flows ◽  
Operating Conditions ◽  
Ceramic Foam ◽  
Spray Combustion ◽  
Hydrocarbon Emissions ◽  
Flame Zone ◽  
Enhanced Heat Transfer ◽  
Firing Rates ◽  
Unburned Hydrocarbon

A study of spray combustion with porous inserts was performed using an on-axis fuel used in a concentric Jet-A. Combustion performance was evaluated by measuring exhaust emissions and flame temperatures for different operating conditions with and without ceramic foam inserts of various properties. The results indicated that the enhanced heat transfer in the flame zone could reduce nitrogen oxides and unburned hydrocarbon emissions. Placing a second porous layer downstream could yield further reductions in both emissions. The results for different firing rates and equivalence ratios revealed the residence time in the porous layer is an important factor regulating combustor performance.

Enhanced Heat Transfer Structure Design for Ion Dump of EAST-NBI System Based on Hypervapotron

2017 ◽  
Author(s):  
Ling Tao ◽  
Chundong Hu ◽  
Yuanlai Xie
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Energy Deposition ◽  
High Energy ◽  
Operating Conditions ◽  
Quasi Steady State ◽  
Enhanced Heat Transfer ◽  
Steady State Operation ◽  
The Future ◽  
Transfer Structure

Ion dump is an important functional component of the Neutral Beam Injection (NBI) system of Experimental Advanced Superconducting Tokamak (EAST) for absorbing un-neutralized particles deflected by deflection magnets during neutralization, and by means of the corresponding measurement and analyzing method on it, the total energy deposition value and instantaneous energy deposition distribution of the deflected ion beam can be obtained. According to the operation mechanism of the NBI system, ion dump is directly subjected to high-energy particle bombardment for long time, the corresponding heat-loaded on its plates is high, so the temperature rise control is demanding. In order to realize the running power of 2–4MW and running pulse length of more than 100s or even 1000s in the future NBI system, the structure of the ion dump must be designed in accordance with the quasi-steady state operation requirements to provide the guarantee for the steady state operation of EAST system. The Hypervapotron structure based on the subcooled boiling principle is used as an alternative structure to enhance the heat transfer of this high-heat-flux component. According to the operating requirements, space requirements, measurement requirements and beam power distribution characteristics, the engineering design and implementation of ion dump based on the enhanced heat transfer structure is realized for the future long pulse quasi-steady NBI system. The computational results of the heat-fluid-solid coupling simulation based on the two-phase heat transfer are also confirmed the feasibility of the proposed ion dump structure under quasi-steady-state operating conditions. This study is of great significance to explore the optimal heat transfer structure for quasi-steady ion dump to realize the high current, quasi-steady state and high power operation of EAST-NBI system.

scholarly journals Multi-Dimensional Performance Evaluation of Heat Exchanger Surface Enhancements

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1406 ◽  
Author(s):  
Hannes Fugmann ◽  
Eric Laurenz ◽  
Lena Schnabel
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchangers ◽  
Energy Efficient ◽  
Reynolds Numbers ◽  
Operating Conditions ◽  
Enhanced Heat Transfer ◽  
Different Types ◽  
Heat Exchanger Surface ◽  
Single Objective

Enhanced heat transfer surfaces allow more energy-efficient, compact and lightweight heat exchangers. Within this study, a method for comparing different types of enhancement and different geometries with multiple objectives is developed in order to evaluate new and existing enhancement designs. The method’s objectives are defined as energy, volume, and mass efficiency of the enhancement. They are given in dimensional and non-dimensional form and include limitations due to thermal conductivity within the enhancement. The transformation to an explicit heat transfer rate per dissipated power, volume, or mass is described in detail. The objectives are visualized for different Reynolds numbers to locate beneficial operating conditions. The multi-objective problem is further on reduced to a single-objective problem by means of weighting factors. The implementation of these factors allows a straightforward performance evaluation based on a rough estimation of the energy, volume, and mass importance set by a decision maker.

Enhanced Cooling via Boiling in Porous Layers: The Effect of Vapor Channels

1999 ◽  
Vol 121 (1) ◽  
pp. 205-210 ◽  
Author(s):  
A. K. Stubos ◽  
J.-M. Buchlin
Keyword(s):  
Heat Transfer ◽  
Porous Layer ◽  
Heated Surface ◽  
Heat Removal ◽  
Vapor Film ◽  
Enhanced Heat Transfer ◽  
Porous Layers

Enhanced heat transfer via boiling in a porous layer covering the heated surface is considered analytically. The effect of vapor channels traversing the porous layer on the power for which a vapor film on the heated surface occurs, is examined by comparing the heat removal capability of the system with and without channels. A significant increase of the attained coolability level is obtained theoretically leading to the possibility of new design configurations for the cooling of intensely heated surfaces.

Predicted Performance of a Ceramic Foam Gas Phase Heat Recuperator for a Solar Thermochemical Reactor

2014 ◽  
Author(s):  
Rohini Bala Chandran ◽  
Aayan Banerjee ◽  
Jane H. Davidson
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Gas Phase ◽  
Heat Recovery ◽  
Porous Alumina ◽  
Porous Ceramic ◽  
Thermal Reduction ◽  
Operating Conditions ◽  
Ceramic Foam ◽  
Solar Thermochemical

The efficiency of solar thermochemical cycles to split water and carbon dioxide depends in large part on highly effective gas phase heat recovery. Heat recovery is imperative for approaches that rely on an inert sweep gas to reach low partial pressures of oxygen during thermal reduction and/or use excess oxidizer to provide a higher thermodynamic driving potential for fuel production. In this paper, we analyze heat transfer and pressure drop of a tube-in-tube ceramic heat exchanger for the operating conditions expected in a prototype solar reactor for isothermal cycling of ceria. The ceramic tubes are filled with reticulated porous ceramic (RPC). The impacts of the selection of the composition and morphology of the RPC on heat transfer and pressure drop are explored via computational analysis. Results indicate a 10 pore per inch (ppi), 80–85% porous alumina RPC yields effectiveness from 85 to 90 percent.

Comparison of Natural Convection Around a Circular Cylinder With Different Geometries of Cylinders Inside a Square Enclosure Filled With Ag-Nanofluid Superposed Porous-Nanofluid Layers

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Salam Hadi Hussain ◽  
Mustafa Salah Rahomey
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Porous Layer ◽  
Volume Fraction ◽  
Mesh Size ◽  
Operating Conditions ◽  
Thermal Conductivity Ratio ◽  
Weighted Residual Method ◽  
Square Enclosure ◽  
Wide Range

Numerical simulations are carried out for fluid flow and natural convection heat transfer induced by a temperature difference between a hot inner cylinder with different geometries (i.e., circular; triangular; elliptic; rectangular; and rhombic) and a cold outer square enclosure filled with nanofluid superposed porous-nanofluid layers. The Darcy–Brinkman model is applied for the saturated porous layer with nanofluid. Moreover, the transport equations (mass, momentum, and energy) are solved numerically using the Galerkin weighted residual method by dividing the domain into two sets of equations for every layer with incorporating a nonuniform mesh size. The considered domains in this investigation are closely examined over a wide range of Rayleigh number (103 ≤ Ra ≤ 106), Darcy number (10−5 ≤ Da ≤ 10−1), the thickness of porous layer (0% ≤ Xp ≤ 100%), thermal conductivity ratio (1 ≤ Rk ≤ 20), and nanoparticle volume fraction (0 ≤ φ ≤ 0.1), respectively. The nanofluid is considered to be composed of Ag-nanoparticle and water as a base fluid. The results showed that the obtained total surfaces-averaged Nusselt numbers of the enclosure, in all cases, at the same operating conditions, the rate of heat transfer from the outer enclosure which the triangular cylinder is located inside is better. Also, as the thickness of the porous layer is increased from 20% to 80%, the free convection performance will decrease significantly (to about 50%) due to the hydrodynamic properties of the porous material.

Sign in / Sign up

Export Citation Format

Share Document