Techniques for Enhancing Durability and Equivalence Ratio Control in a Rich-Lean, Three-Stage, Ground Power Gas Turbine Combustor
This effort summarizes the work performed under Task IV, Sector Rig Tests of the CRT - Critical Research and Support Technology Program, a Department of Energy funded project. The rig tests of a can-type combustor were performed to demonstrate two advanced ground power engine combustor concepts: steam cooled rich-burn combustor primary zones for enhanced durability; and variable combustor geometry for three stage combustion equivalence ratio control. Both concepts proved to be highly successful in achieving their desired objectives. The steam cooling reduced peak liner temperatures to less than 800 K. This offers the potential of both long life and reduced use of strategic materials for liner fabrication. Three degrees of variable geometry were successfully implemented to control airflow distribution within the combustor. One was a variable blade angle axial flow air swirler to control primary airflow while the other two consisted of rotating bands to control secondary and tertiary or dilution air flow.Copyright © 1982 by ASME
An analytical study of nitrogen oxides and carbon monoxide emissions in hydrocarbon combustion with added nitrogen, preliminary results
AN ANALYTICAL STUDY OF NITROGEN OXIDES AND CARBON MONOXIDEEMISSIONS IN HYDROCARBON CONRUSTION WITH ADDEDNITROGEN - PRELIMINARY RESULVEby David A. BittkerNational Aeronautics and Space AdministrationLewis Research CenterCleveland, OhiohasINTRODUCTIONOne of the major efforts in the development ofSee turbines for ground power generation is theiradaptation to the use of coal-derived liquid fuels.The wide range of properties of these synthetic liquidfuels leads to many problems. A recent summary ofcoal derived liquid fuel properties and their poten-tial problems in turbine combustion is given in Ref. 1.The present paper focuses on the problem of increasedemissions. The main question is how much the oxidesof nitrogen (NOx) emissions will be increased by theincreased amount of organic nitrogen compounds con-tained in these synthetic liquids. Another questionis whether this fuel-bound nitrogen (FBN) will haveany significant effect upon the carbon monoxide (CO)emissions from synthetic fuel combustion.The present work was undertaken to investigatethese questions as one part of the Critical Researchand Technology program funded by the Department ofEnergy at the Lewis Research Center. The primary pur-pose of this work is to analytically determine the ef-fect of combustion operating conditions on the conver-sion of FBN to NDx. The effect of FBN and of operat-ing conditions on CO emissions was also examined.Propane-air was chosen as the combustible mixture forthe first series of computations. The combustor modelwas assumed to be a two-stage, adiabatic, perfectly-stirred reactor. Chemical modeling of the oxidationof propane and the formation of NOx was done using afifty-seven reaction mechanism. The use of two-stagecombustion to minimize NOx formatir has been reportedby several investigators (2 to 4). The greatest NOx1Numbers in parentheses designate references atend of paper.reduction is achieved by burning with a rich primarymixture and then diluting with air for quite leansecond-stage combustion.A wide range of operating conditions was used forthese computations. Primary equivalence ratio, qtp,was varied from 0.5 to 1.7. Dilution air was added inthe secondary zone, as necessary, to give a secondaryequivalence ratio, ms, of either 0.5 or 0.7. Primarystage residence time varied from approximately 12 to20 msec and secondary stage residence times of approxi-mately 1, 2, and 3 cosec were used. Three differentamounts of FRN were used in the computations, namely0.5, 1.0, and 2.0 percent by weight of the initialfuel. All computations were performed for a constantpressure of 5 stm and initial mixture temperaturesranged from 608 to 650 K.Computations were performed using the NASA LewisGeneral Chemical Kinetics Program (5), which was modi-to perform stirred-reactor model computations. Thenonlinear algebraic equations given in Refs. 6 and 7for multicomponent, chemically rate-limited homoge-neous reaction in a perfectly-stirred reactor wereused. Solution of these equations by the modifiedNewton-Raphs7n iteration procedure given in Ref. 6 wasprogrammed and incorporated as a subroutine into thegeneral chemical kinetics program.Results are presented for NOx and CO concentra-tions as a function of (pp,
Flow in a branching open channel: a review
Branching channel flow refers to any side water withdrawals from rivers or main channels. Branching channels have wide application in many practical projects, such as irrigation and drainage network systems, water and waste water treatment plants, and many water resources projects. In the last decades, extensive theoretical and experimental investigations of the branching open channels have been carried out to understand the characteristics of this branching flow, varying from case studies to theoretical and experimental investigations. The objectives of this paper are to review and summarise the relevant literatures regarding branching channel flow. These literatures were reviewed based on flow characteristics, physical characteristics, and modeling of the branching flow. Investigations of the flow into branching channel show that the branching discharge depends on many interlinked parameters. It increases with the decreasing of the main channel flow velocity and Froude number at the upstream of the branch channel junction. Also it increases with the increasing of the branch channel bed slope. In subcritical flow, water depth in the branch channel is always lower than the main channel water depth. The flow diversion to the branch channel leads to an increase of water depth at the downstream of the main channel. From the review, it is important to highlight that most of the study concentrated on flow characteristics in a right angle branch channel with a rigid boundary. Investigations on different branching angles with movable bed have still to be explored.