{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/33098"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/33098","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"A Method to Control Turbofan Engine Starting by Varying Compressor Surge Valve Bleed","abstract":"This thesis reports the results of a study of the starting conditions of a turbofan engine. The research focused on ways to minimize turbine inlet temperature while maintaining an adequate compressor stall margin during engine start by varying the surge valve bleed. Varying the surge valve bleed was also shown to reduce compressor and fan required torque. A new method of turbofan engine component characteristic map extrapolation was developed. This novel method uses incompressible similarity laws, but compressibility effects of the flow are reflected by changing the exponent used in the similarity laws. These extrapolated component characteristic maps were tested in a simulation of the turbofan engine by stepping engine speed from close to ignition speed to idle speed. The simulation predictions were verified by comparing them to experimental engine performance data. Lastly, a parametric study of starting surge valve flow area schedule was performed to reduce turbine temperatures while maintaining adequate stall margin. Minimizing turbine inlet temperatures during start-up when turbine components are cold will minimize thermal shock and thereby extend turbine component life.","abstract_html":"This thesis reports the results of a study of the starting conditions of a turbofan engine. The research focused on ways to minimize turbine inlet temperature while maintaining an adequate compressor stall margin during engine start by varying the surge valve bleed. Varying the surge valve bleed was also shown to reduce compressor and fan required torque. A new method of turbofan engine component characteristic map extrapolation was developed. This novel method uses incompressible similarity laws, but compressibility effects of the flow are reflected by changing the exponent used in the similarity laws. These extrapolated component characteristic maps were tested in a simulation of the turbofan engine by stepping engine speed from close to ignition speed to idle speed. The simulation predictions were verified by comparing them to experimental engine performance data. Lastly, a parametric study of starting surge valve flow area schedule was performed to reduce turbine temperatures while maintaining adequate stall margin. Minimizing turbine inlet temperatures during start-up when turbine components are cold will minimize thermal shock and thereby extend turbine component life.","abstract_has_math":false,"creators":["Sexton, Wayne Randolph"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":["Ng, Wing Fai","King, Peter S."],"year":2001,"date_issued":"2001-05-14","date_published":"2001-05-14","updated_at":"2026-07-22T22:20:16Z","subjects":[],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05222001-145840"],"render_values":[{"text":"etd-05222001-145840","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/33098","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Ng, Wing Fai","King, Peter S."]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Sexton, Wayne Randolph"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:38:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:38:02Z","2002-05-23"]},{"key":"dc:date.issued","label":"Date","values":["2001-05-14"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05222001-145840"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/33098"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis reports the results of a study of the starting conditions of a turbofan engine. The research focused on ways to minimize turbine inlet temperature while maintaining an adequate compressor stall margin during engine start by varying the surge valve bleed. Varying the surge valve bleed was also shown to reduce compressor and fan required torque. A new method of turbofan engine component characteristic map extrapolation was developed. This novel method uses incompressible similarity laws, but compressibility effects of the flow are reflected by changing the exponent used in the similarity laws. These extrapolated component characteristic maps were tested in a simulation of the turbofan engine by stepping engine speed from close to ignition speed to idle speed. The simulation predictions were verified by comparing them to experimental engine performance data. Lastly, a parametric study of starting surge valve flow area schedule was performed to reduce turbine temperatures while maintaining adequate stall margin. Minimizing turbine inlet temperatures during start-up when turbine components are cold will minimize thermal shock and thereby extend turbine component life."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["A Method to Control Turbofan Engine Starting by Varying Compressor Surge Valve Bleed"]}]}],"canonical_facts":{"dc:contributor.committeemember":["Ng, Wing Fai","King, Peter S."],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Sexton, Wayne Randolph"],"dc:date.accessioned":["2014-03-14T20:38:02Z"],"dc:date.available":["2014-03-14T20:38:02Z","2002-05-23"],"dc:date.issued":["2001-05-14"],"dc:description.abstract":["This thesis reports the results of a study of the starting conditions of a turbofan engine. The research focused on ways to minimize turbine inlet temperature while maintaining an adequate compressor stall margin during engine start by varying the surge valve bleed. Varying the surge valve bleed was also shown to reduce compressor and fan required torque. A new method of turbofan engine component characteristic map extrapolation was developed. This novel method uses incompressible similarity laws, but compressibility effects of the flow are reflected by changing the exponent used in the similarity laws. These extrapolated component characteristic maps were tested in a simulation of the turbofan engine by stepping engine speed from close to ignition speed to idle speed. The simulation predictions were verified by comparing them to experimental engine performance data. Lastly, a parametric study of starting surge valve flow area schedule was performed to reduce turbine temperatures while maintaining adequate stall margin. Minimizing turbine inlet temperatures during start-up when turbine components are cold will minimize thermal shock and thereby extend turbine component life."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-05222001-145840"],"dc:identifier.uri":["http://hdl.handle.net/10919/33098"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["A Method to Control Turbofan Engine Starting by Varying Compressor Surge Valve Bleed"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:16Z"}