{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20485"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20485","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Investigation of the condensing and expansion behaviors of alternative refrigerants","abstract":"This study examines the heat transfer and pressure drop performance of R22 and R502 alternatives while condensing in an enhanced tube with 0% to 3% oil and while expanding in a capillary tube. The capillary tube study examined the mass flow rate of refrigerants while expanding, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures.","abstract_html":"This study examines the heat transfer and pressure drop performance of R22 and R502 alternatives while condensing in an enhanced tube with 0% to 3% oil and while expanding in a capillary tube. The capillary tube study examined the mass flow rate of refrigerants while expanding, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures.","abstract_has_math":false,"creators":["Meyer, John Joseph"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Dunn, William E."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:40:35Z","date_published":"2011-05-07T12:40:35Z","updated_at":"2026-07-22T22:25:16Z","subjects":["Engineering, Mechanical"],"languages":["eng"],"rights":["Copyright 1996 Meyer, John Joseph"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591198348","AAI9712377","(UMI)AAI9712377"],"render_values":[{"text":"9780591198348","href":null,"code":true},{"text":"AAI9712377","href":null,"code":true},{"text":"(UMI)AAI9712377","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20485","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dunn, William E."]},{"key":"dc:creator","label":"Author","values":["Meyer, John Joseph"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:40:35Z","10000-01-01","1996"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Mechanical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1996 Meyer, John Joseph"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["9780591198348","AAI9712377","(UMI)AAI9712377","http://hdl.handle.net/2142/20485"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["This study examines the heat transfer and pressure drop performance of R22 and R502 alternatives while condensing in an enhanced tube with 0% to 3% oil and while expanding in a capillary tube. The capillary tube study examined the mass flow rate of refrigerants while expanding, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures.","We found that the pressure drop of the helically enhanced tube is best predicted by using a friction factor set equal to a constant multiplied by the friction factor of a smooth tube, not a constant roughness. Also, the addition of oil has a pressure lowering effect for low qualities, where most of the flow is liquid, and a pressure raising effect at high qualities, where most of the flow is vapor in contact with a liquid oil film.","When adjusting the two-phase pressure-temperature relationship for the presence of oil, it was noticed that for each mixture there was a consistent deviation between the expected condensing temperature and the measured value. This discrepancy results from errors in the model used to predict the two-phase properties of the blends, and has been accounted for in the reduction of the data. We found that oil has a significant effect on heat transfer coefficients at qualities above about 0.7, but very little effect at lower qualities. Also, the performance of mixtures increases more rapidly than that of a single component refrigerant as the mass flux is increased.","The metastable region of a capillary tube was found to be much more predictable than previously thought. A new and revealing data taking technique, which takes the history of the system into account, allowed for the discovery of a hysteresis effect in the mass flow rate as the level of inlet subcooling is increased and decreased. This finding may have a profound impact on the future of capillary tube data acquisition and modeling.","Made available in DSpace on 2011-05-07T12:40:35Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712377.pdf: 16974614 bytes, checksum: 3f22817497511b086875d1923186b49c (MD5) Previous issue date: 1996","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:44:12Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:19:26-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Investigation of the condensing and expansion behaviors of alternative refrigerants"]}]}],"canonical_facts":{"dc:contributor":["Dunn, William E."],"dc:creator":["Meyer, John Joseph"],"dc:date":["2011-05-07T12:40:35Z","10000-01-01","1996"],"dc:description":["This study examines the heat transfer and pressure drop performance of R22 and R502 alternatives while condensing in an enhanced tube with 0% to 3% oil and while expanding in a capillary tube. The capillary tube study examined the mass flow rate of refrigerants while expanding, with an emphasis on the nature of the metastable region for both single component refrigerants and mixtures.","We found that the pressure drop of the helically enhanced tube is best predicted by using a friction factor set equal to a constant multiplied by the friction factor of a smooth tube, not a constant roughness. Also, the addition of oil has a pressure lowering effect for low qualities, where most of the flow is liquid, and a pressure raising effect at high qualities, where most of the flow is vapor in contact with a liquid oil film.","When adjusting the two-phase pressure-temperature relationship for the presence of oil, it was noticed that for each mixture there was a consistent deviation between the expected condensing temperature and the measured value. This discrepancy results from errors in the model used to predict the two-phase properties of the blends, and has been accounted for in the reduction of the data. We found that oil has a significant effect on heat transfer coefficients at qualities above about 0.7, but very little effect at lower qualities. Also, the performance of mixtures increases more rapidly than that of a single component refrigerant as the mass flux is increased.","The metastable region of a capillary tube was found to be much more predictable than previously thought. A new and revealing data taking technique, which takes the history of the system into account, allowed for the discovery of a hysteresis effect in the mass flow rate as the level of inlet subcooling is increased and decreased. This finding may have a profound impact on the future of capillary tube data acquisition and modeling.","Made available in DSpace on 2011-05-07T12:40:35Z (GMT). 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