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Title: Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors

Abstract

The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high-fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation, a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet tranformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validatedmore » against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.« less

Authors:
Publication Date:
Research Org.:
Leland Stanford Junior University
Sponsoring Org.:
USDOE
OSTI Identifier:
1001422
DOE Contract Number:
FG26-08NT43325
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; BURNERS; COMBUSTION; COMBUSTORS; DATA; DESIGN; FLAME PROPAGATION; FLAMES; FORECASTING; HYDROGEN; INCLUSIONS; LEWIS NUMBER; OPTIMIZATION; SIMULATION; THERMAL DIFFUSION; TRANSFORMATIONS; TURBINES

Citation Formats

Heinz Pitsch. Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors. United States: N. p., 2010. Web. doi:10.2172/1001422.
Heinz Pitsch. Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors. United States. doi:10.2172/1001422.
Heinz Pitsch. Mon . "Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors". United States. doi:10.2172/1001422. https://www.osti.gov/servlets/purl/1001422.
@article{osti_1001422,
title = {Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors},
author = {Heinz Pitsch},
abstractNote = {The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high-fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation, a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet tranformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validated against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.},
doi = {10.2172/1001422},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 31 00:00:00 EDT 2010},
month = {Mon May 31 00:00:00 EDT 2010}
}

Technical Report:

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  • The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation; a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewismore » number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet transformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validated against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.« less
  • In this document we report on the status of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Enabling Computational Technologies (ECT) effort. In particular, we provide the context for ECT In the broader NEAMS program and describe the three pillars of the ECT effort, namely, (1) tools and libraries, (2) software quality assurance, and (3) computational facility (computers, storage, etc) needs. We report on our FY09 deliverables to determine the needs of the integrated performance and safety codes (IPSCs) in these three areas and lay out the general plan for software quality assurance to meet the requirements of DOE andmore » the DOE Advanced Fuel Cycle Initiative (AFCI). We conclude with a brief description of our interactions with the Idaho National Laboratory computer center to determine what is needed to expand their role as a NEAMS user facility.« less
  • This quarterly report describes work performed on the design, fabrication, and testing of a new device for atomizing coal-water fuel (CWF). The device is referred to as an opposed-jet atomizer, and differs from conventional atomizer designs in that the atomization results largely from the collision of two opposing streams of CWF flowing towards each other. Normal to the plane of the opposing streams of CWF, a blast of air crosses the colliding streams and not only aids in atomization, but also directs the spray into the combustion zone of a combustor. The project is divided into 11 tasks, each ofmore » which is intended to allow the goal of developing a workable CWF atomization device to be achieved. The device is to be designed, and a prototype built. Next the atomizer is to be tested with water. Upon achieving the successful atomization of water, CWF will be atomized under cold-flow (i.e., noncombustion) conditions. The results of the cold-flow testing are to be reviewed, and any necessary modifications to the atomizer are to be approved. After modification, if necessary, the opposed-jet atomizer will be tested under actual combustion conditions. An evaluation of the combustion results will determine the effectiveness of the device. 1 ref., 4 tabs.« less
  • The primary objective of this project is to develop an atomizer to be used for the combustion of coal-water fuel (CWF) in small- to medium-sized boilers. The envisoned atomizer utilizes two opposing streams of CWF which collide and cause a spray to be produced. A blast of air crossing the streams directs the spray into the combustion zone of a boiler. It is hoped that the opposed-jet atomizer will produce MMD sprays of fine droplet sizes, possibly approaching 10 microns. A CWF was prepared at 40% solids that was 100% minus 38 microns (400 mesh). Good-quality sprays were produced atmore » 125 psig using the smaller orifice of 0.024 inch. Some large droplets were observed, but in general the spray was quite fine and mist-like. This encouraging result has prompted us to perform particle size measurements on the droplets produced. These measurements will be presented in subsequent reports. 3 figs.« less
  • Atlantic Research has undertaken a program to design, fabricate and test this new concept in coal-water fuel atomizers. The device employs two diametrically opposed jets of CWF which impinge on each other at high velocity. An air blast is directed at the impact zone of the two jets and the resulting high energy collision of all streams serves to break up the slurry fuel into fine droplets which are then directed by the air blast into the combustion zone. Prototypes of this atomizer have been built and tested under cold flow conditions using both water and CWF sprays. Based onmore » the cold flow result with the prototypes, an atomizer has been fabricated for installation in a 1 MMBTU/H research tunnel-type'' furnace. A comprehensive testing program was conducted to evaluate the atomizer under firing conditions. The parameters covered in the test plan included CWF firing rate, atomizing air pressure, secondary air preheat temperature, secondary air diffuser design, CWF viscosity and solid content, CWF preheat temperature, and coal type. The effects of these parameters on combustion efficiency have been determined. 3 refs., 20 figs., 26 tabs.« less