{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:ucin1353154991"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:ucin1353154991","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach","abstract":"A Non-Conventional Loop Heat Pipe, much different from a conventional LHP, is employed in cooling Light Emitting Diode luminaries in high bay lighting. Different from a conventional LHP, these devices use the entrainment phenomenon to passively transport waste thermal energy dissipated from the LEDs into ambient air. Unlike a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, the condenser and the sub-cooler. Each of these sections is individually studied, understood, and modeled. The data collected from the experiments performed on the non-conventional LHP are utilized in formulating some empirical coefficients for these models such as the convection heat transfer coefficient for the ambient air, a few thermal resistances in the evaporator package and a constant temperature difference between the bulk fluid and the walls of the tube in the sub-cooler section of the device. An attempt to mathematically model the non-conventional LHP provides some insights into the relationship of the nature of working fluid with the quality of the two-phase mixture, and the mass flow rate.The parametric model throws light on the various parameters that are necessary for the LHP to successfully remove a certain amount of thermal energy from the LEDs. Different parameters that could potentially increase the temperature of the board are studied and delineated in this work. The design model illustrates a method for estimating the geometry of the device for cooling a specific LED power for a particular application. The attempt to model the current device is a first step in trying to design a product capable of cooling a 1000 W equivalent LED fixture. Additionally, these models could potentially lay the foundation for understanding the relationship between the mass flow rate, the quality of the working fluid entering the condenser due to entrainment, the pressure drop across the interface and the amount of latent energy lost in the condenser of this device.","abstract_html":"A Non-Conventional Loop Heat Pipe, much different from a conventional LHP, is employed in cooling Light Emitting Diode luminaries in high bay lighting. Different from a conventional LHP, these devices use the entrainment phenomenon to passively transport waste thermal energy dissipated from the LEDs into ambient air. Unlike a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, the condenser and the sub-cooler. Each of these sections is individually studied, understood, and modeled. The data collected from the experiments performed on the non-conventional LHP are utilized in formulating some empirical coefficients for these models such as the convection heat transfer coefficient for the ambient air, a few thermal resistances in the evaporator package and a constant temperature difference between the bulk fluid and the walls of the tube in the sub-cooler section of the device. An attempt to mathematically model the non-conventional LHP provides some insights into the relationship of the nature of working fluid with the quality of the two-phase mixture, and the mass flow rate.The parametric model throws light on the various parameters that are necessary for the LHP to successfully remove a certain amount of thermal energy from the LEDs. Different parameters that could potentially increase the temperature of the board are studied and delineated in this work. The design model illustrates a method for estimating the geometry of the device for cooling a specific LED power for a particular application. The attempt to model the current device is a first step in trying to design a product capable of cooling a 1000 W equivalent LED fixture. Additionally, these models could potentially lay the foundation for understanding the relationship between the mass flow rate, the quality of the working fluid entering the condenser due to entrainment, the pressure drop across the interface and the amount of latent energy lost in the condenser of this device.","abstract_has_math":false,"creators":["Remella Siva Rama, Karthik"],"institution":"University of Cincinnati","degree_name":"MS","degree_level":"masters","degree_discipline":"Engineering and Applied Science: Mechanical Engineering","degree_department":null,"school":null,"contributors":["Gerner, Frank"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012","date_published":"2012","updated_at":"2026-07-24T03:36:23Z","subjects":["Mechanical Engineering","Entrainment","Loop Heat Pipe","LED cooling","Parametric model","Design model"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gerner, Frank"]},{"key":"dc:creator","label":"Author","values":["Remella Siva Rama, Karthik"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012"]},{"key":"dc:publisher","label":"Institution","values":["University of Cincinnati / OhioLINK"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Engineering and Applied Science: Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["MS"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Cincinnati"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Mechanical Engineering","Entrainment","Loop Heat Pipe","LED cooling","Parametric model","Design model"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A Non-Conventional Loop Heat Pipe, much different from a conventional LHP, is employed in cooling Light Emitting Diode luminaries in high bay lighting. Different from a conventional LHP, these devices use the entrainment phenomenon to passively transport waste thermal energy dissipated from the LEDs into ambient air. Unlike a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, the condenser and the sub-cooler. Each of these sections is individually studied, understood, and modeled. The data collected from the experiments performed on the non-conventional LHP are utilized in formulating some empirical coefficients for these models such as the convection heat transfer coefficient for the ambient air, a few thermal resistances in the evaporator package and a constant temperature difference between the bulk fluid and the walls of the tube in the sub-cooler section of the device. An attempt to mathematically model the non-conventional LHP provides some insights into the relationship of the nature of working fluid with the quality of the two-phase mixture, and the mass flow rate.The parametric model throws light on the various parameters that are necessary for the LHP to successfully remove a certain amount of thermal energy from the LEDs. Different parameters that could potentially increase the temperature of the board are studied and delineated in this work. The design model illustrates a method for estimating the geometry of the device for cooling a specific LED power for a particular application. The attempt to model the current device is a first step in trying to design a product capable of cooling a 1000 W equivalent LED fixture. Additionally, these models could potentially lay the foundation for understanding the relationship between the mass flow rate, the quality of the working fluid entering the condenser due to entrainment, the pressure drop across the interface and the amount of latent energy lost in the condenser of this device."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.170","2.16 MB"]},{"key":"dc:title","label":"Title","values":["Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach"]}]}],"canonical_facts":{"dc:contributor":["Gerner, Frank"],"dc:creator":["Remella Siva Rama, Karthik"],"dc:date":["2012"],"dc:description":["A Non-Conventional Loop Heat Pipe, much different from a conventional LHP, is employed in cooling Light Emitting Diode luminaries in high bay lighting. Different from a conventional LHP, these devices use the entrainment phenomenon to passively transport waste thermal energy dissipated from the LEDs into ambient air. Unlike a conventional LHP, the pressure drop across the liquid-vapor interface in the evaporator wick is not very high. In the present work, two different mathematical models – a parametric model and a design model, are developed. The device is partitioned into three prominent sections – the evaporator, the condenser and the sub-cooler. Each of these sections is individually studied, understood, and modeled. The data collected from the experiments performed on the non-conventional LHP are utilized in formulating some empirical coefficients for these models such as the convection heat transfer coefficient for the ambient air, a few thermal resistances in the evaporator package and a constant temperature difference between the bulk fluid and the walls of the tube in the sub-cooler section of the device. An attempt to mathematically model the non-conventional LHP provides some insights into the relationship of the nature of working fluid with the quality of the two-phase mixture, and the mass flow rate.The parametric model throws light on the various parameters that are necessary for the LHP to successfully remove a certain amount of thermal energy from the LEDs. Different parameters that could potentially increase the temperature of the board are studied and delineated in this work. The design model illustrates a method for estimating the geometry of the device for cooling a specific LED power for a particular application. The attempt to model the current device is a first step in trying to design a product capable of cooling a 1000 W equivalent LED fixture. Additionally, these models could potentially lay the foundation for understanding the relationship between the mass flow rate, the quality of the working fluid entering the condenser due to entrainment, the pressure drop across the interface and the amount of latent energy lost in the condenser of this device."],"dc:format":["application/pdf","p.170","2.16 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353154991"],"dc:language":["English"],"dc:publisher":["University of Cincinnati / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"dc:subject":["Mechanical Engineering","Entrainment","Loop Heat Pipe","LED cooling","Parametric model","Design model"],"dc:title":["Steady State Mathematical Modeling of Non-Conventional Loop Heat Pipes: A Parametric and a Design Approach"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Engineering and Applied Science: Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["MS"],"thesis:institution_name":["University of Cincinnati"]},"updated_at":"2026-07-24T03:36:23Z"}