Experimental study of thermoacoustic oscillations inside a small-scale power generator combustor
department or school: Applied Science, Faculty of
department or school: Engineering, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Heydarlaki, Ramin
issued: 2020-10-08T17:40:32Z
issued: 2020
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Thermoacoustic (pressure and heat release rate) oscillations can be detrimental to the operation of engineering equipment ranging from large-scale gas turbine engines (hundreds of mega watts) to small-scale power generators (few kilo watts). The focus of this thesis is thermoacoustic oscillations occurring in the combustor of a small-scale power generator. In this combustor, circulation of exhaust gas around reacting gas is utilized to increase the combustor thermal efficiency and is facilitated by using a stagnation wall. Two experimental setups are utilized. The former is a close replication of the engineering equipment, and the latter is a simplified version of the equipment, but it provides optical accessibility. In the experiments, the fuel-air equivalence ratio and air flowrate are varied from 0.7to 1.4 and 50 to 180 SLPM, respectively. For the experiments related to the first setup, pressure and temperature measurements are performed. For the second setup, both pressure and flame chemiluminescence measurements are acquired. For the first setup, the characteristics of thermoacoustic oscillations while the wall-temperature increases and how the initial wall-temperature influences these characteristics are investigated. It is shown, that for cold-start conditions, the pressure transitions from chaotic to limit cycle, chaotic, bursting, and then limit cycle oscillations. For warm-start conditions, however, the pressure features a combination of both large- and small-amplitude limit cycle oscillations. For the second setup, contributions of different types of thermoacoustic modes to Rayleigh gain is investigated. Results show that, for fuel-air equivalence ratio of 0.7, thermoacoustic oscillations feature natural structural (21 Hz) and acoustic (61 Hz) modes. However, oscillations related to fuel-air equivalence ratio of 0.9 feature intrinsic modes near 240 and 290 Hz, in addition to structural and acoustic modes. It is demonstrated that acoustic and structural mo…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/76268
note: Experimental study of thermoacousticoscillations inside a small-scale powergenerator combustorbyRamin HeydarlakiA thesis submitted in partial fulfillment ofthe requirements for the degree ofMASTER OF APPLIED SCIENCEinThe College of Graduate Studies(Mechanical Engineering)THE UNIVERSITY OF BRITISH COLUMBIA(Okanagan)September 2020 Ramin Heydarlaki, 2020The following individuals certify that they have read, and recommend to the College ofGraduate Studies for acceptance, a thesis/dissertation entitled:Experimental study of thermoacoustic oscillations inside a small-scale power generator com-bustorsubmitted by Ramin Heydarlaki in partial fulfillment of the requirements of the degree ofMaster of Applied ScienceDr. Sina Kheirkhah, UBC, School of EngineeringSupervisorDr. Joshua Brinkerhoff, UBC, School of EngineeringSupervisory Committee MemberDr. Patrick Kirchen, UBC, Mechanical EngineeringSupervisory Committee MemberDr. Jonathan Holzman, UBC, School of EngineeringUniversity ExamineriiAbstractThermoacoustic (pressure and heat release rate) oscillations can be detrimental to the oper-ation of engineering equipment ranging from large-scale gas turbine engines (hundreds of megawatts) to small-scale power generators (few kilo watts). The focus of this thesis is thermoacous-tic oscillations occurring in the combustor of a small-scale power generator. In this combustor,circulation of exhaust gas around reacting gas is utilized to increase the combustor thermalefficiency and is facilitated by using a stagnation wall.Two experimental setups are utilized. The former is a close replication of the engineeringequipment, and the latter is a simplified version of the equipment, but it provides optical acces-sibility. In the experiments, the fuel-air equivalence ratio and air flowrate are varied from 0.7to 1.4 and 50 to 180 SLPM, respectively. For the experiments related to the first setup, pres-sure and temperature measurements are performed. For the second setup, both pressure andflame…
has type: Thesis/Dissertation
date issued: 2020-11
is shown at: 10.14288/1.0394723
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/76268