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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorPeles, Yoav
dc.contributorPlawsky, Joel L., 1957-
dc.contributorBorca-Tasçiuc, Theodorian
dc.contributorChung, Aram
dc.contributor.authorVutha, Ashwin Kumar
dc.date.accessioned2021-11-03T08:53:07Z
dc.date.available2021-11-03T08:53:07Z
dc.date.created2017-11-10T12:47:50Z
dc.date.issued2017-08
dc.identifier.urihttps://hdl.handle.net/20.500.13015/2047
dc.descriptionAugust 2017
dc.descriptionSchool of Engineering
dc.description.abstractIn this dissertation, a novel approach is presented to control surface temperatures and enhance heat transfer in microchannel flow boiling. Experiments were performed using a microdevice with resistance-temperature detectors (RTDs) as heating and sensing elements. The flow was visualized through a high-speed imaging system. A transverse jet in crossflow was used to control surface temperatures and to effectively suppress dryout, at nominal heat fluxes up to 14 W/cm². A setpoint-based feedback control mechanism was evaluated under conditions of steady and transient heating, and its performance was compared to the reference case without active control. Maximum surface-averaged heat transfer enhancements of 130% and 127% were obtained with active control for steady and unsteady heating respectively. Transient local temperature measurements were made and used to compute the corresponding heat transfer coefficients. Active control allowed the local surface temperatures to be maintained in the vicinity of the specified setpoint in most cases.
dc.description.abstractLiquid cooling with phase change, or flow boiling, offers promising solutions to the challenge posed by heat generation in electronics. However, multiphase flow in narrow conduits comes with associated concerns such as unstable operation, dryout and critical heat flux (CHF), all of which result in high surface temperatures. Practical realization of two-phase heat exchangers in the electronics industry is hindered by the lack of universal predictive tools and control mechanisms that will address these concerns.
dc.description.abstractDesign of electronic equipment has evolved over the past few decades to incorporate advanced functionality while simultaneously reducing their dimensions. An undesirable consequence of such progress is the tendency of contemporary electronics to dissipate heat over diminishing length scales, leading to increased heat fluxes and surface temperatures. Equipment designers are faced with the predicament of engineering their products to reject any excess heat that will result in unsafe operating temperatures. Steady advances in the electronics industry have rendered air cooled heat exchangers inadequate. Furthermore, single-phase liquid flow is also being stretched to its limits by increasing heat fluxes.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectMechanical engineering
dc.titleActive control of surface temperatures in microchannel flow boiling
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid178551
dc.digitool.pid178552
dc.digitool.pid178553
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Mechanical, Aerospace, and Nuclear Engineering


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