An investigation was conducted into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable spacing between obstacles. The goal of this investigation was to correlate the spacing between obstacles and the blockage ratio of the obstacles with the detonation success and the shortening of the DDT section. The ten cases that achieved the highest percentage of detonations were investigated further to determine the distance needed for the deflagration-to-detonation transition. A 33% blockage ratio was the most successful to induce turbulence and not quench the detonation wave. With these conditions, DDT was achievable with 100% success in a section whose length was 31 times the inner diameter of the DDT section. Detonation was unachievable in 82 times the inner diameter in a \"smooth\" tube. This is a greater than 63% decrease in detonation transition length. This decrease in length will further facilitate the integration of pulse detonation engines into gas turbine engines.
","abstract_html":"<p>An investigation was conducted into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable spacing between obstacles. The goal of this investigation was to correlate the spacing between obstacles and the blockage ratio of the obstacles with the detonation success and the shortening of the DDT section. The ten cases that achieved the highest percentage of detonations were investigated further to determine the distance needed for the deflagration-to-detonation transition. A 33% blockage ratio was the most successful to induce turbulence and not quench the detonation wave. With these conditions, DDT was achievable with 100% success in a section whose length was 31 times the inner diameter of the DDT section. Detonation was unachievable in 82 times the inner diameter in a "smooth" tube. This is a greater than 63% decrease in detonation transition length. This decrease in length will further facilitate the integration of pulse detonation engines into gas turbine engines.</p>","abstract_has_math":false,"creators":["Gagnon, Nicole"],"institution":null,"degree_name":"Master of Science in Aerospace Engineering","degree_level":"Thesis - Open Access","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-05-01T07:00:00Z","date_published":"2016-05-01T07:00:00Z","updated_at":"2026-07-27T19:26:02Z","subjects":["axial spacing","variable blockage","pulse detonation engine","Aerospace Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://commons.erau.edu/edt/211","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Gagnon, Nicole"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis - Open Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science in Aerospace Engineering"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["axial spacing","variable blockage","pulse detonation engine","Aerospace Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://commons.erau.edu/edt/211"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["An investigation was conducted into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable spacing between obstacles. The goal of this investigation was to correlate the spacing between obstacles and the blockage ratio of the obstacles with the detonation success and the shortening of the DDT section. The ten cases that achieved the highest percentage of detonations were investigated further to determine the distance needed for the deflagration-to-detonation transition. A 33% blockage ratio was the most successful to induce turbulence and not quench the detonation wave. With these conditions, DDT was achievable with 100% success in a section whose length was 31 times the inner diameter of the DDT section. Detonation was unachievable in 82 times the inner diameter in a \"smooth\" tube. This is a greater than 63% decrease in detonation transition length. This decrease in length will further facilitate the integration of pulse detonation engines into gas turbine engines.
"]},{"key":"dc:title","label":"Title","values":["The Effect of Axial Spacing of Constant and Variable Blockages on the Deflagration-to-Detonation Transition in a Pulse Detonation Engine"]}]}],"canonical_facts":{"dc:creator":["Gagnon, Nicole"],"dc:description.abstract":["An investigation was conducted into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable spacing between obstacles. The goal of this investigation was to correlate the spacing between obstacles and the blockage ratio of the obstacles with the detonation success and the shortening of the DDT section. The ten cases that achieved the highest percentage of detonations were investigated further to determine the distance needed for the deflagration-to-detonation transition. A 33% blockage ratio was the most successful to induce turbulence and not quench the detonation wave. With these conditions, DDT was achievable with 100% success in a section whose length was 31 times the inner diameter of the DDT section. Detonation was unachievable in 82 times the inner diameter in a \"smooth\" tube. This is a greater than 63% decrease in detonation transition length. This decrease in length will further facilitate the integration of pulse detonation engines into gas turbine engines.
"],"dc:identifier":["https://commons.erau.edu/edt/211"],"dc:subject":["axial spacing","variable blockage","pulse detonation engine","Aerospace Engineering"],"dc:title":["The Effect of Axial Spacing of Constant and Variable Blockages on the Deflagration-to-Detonation Transition in a Pulse Detonation Engine"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Thesis - Open Access"],"thesis:degree_name":["Master of Science in Aerospace Engineering"]},"updated_at":"2026-07-27T19:26:02Z"}