TWO-PHASE EVAPORATOR REDUCED ORDER MODEL DEVELOPMENT FOR FIBER-COUPLED LASER DIODES SYSTEMS
Abstract
Abstract TWO-PHASE EVAPORATOR REDUCED ORDER MODEL DEVELOPMENT FORFIBER-COUPLED LASER DIODES SYSTEMSDirected energy weapons that u"tilize pulsed-power laser diodes are a strategic technology for the U.S., and integration onto existing and new platforms will incre""ase cooling demand requirements. This in turn reduces how many shots can be delivered, and reduces overall system efficiency. During"" system operation, the average heat load is substantially less than the pulsedload, and, therefore, there is an opportunity to redu"ce power consumed for thermal management systems if thermal energy storage is included in the cooling loop. Incorporating a two-phas"e microchannel evaporator could also substantially reduce the thermal resistance between the fluid and diode surface, which allows t""he temperature lift for integrated vapor compression systems toreduce, thus decreasing the amount of electrical power required for"" cooling even further. However, two-phase flow through small channels can yield substantial increases in pressure drop, potentially"" off-setting this benefit. Unfortunately, a transient two-phase evaporator model does not exist to understand this tradeoff, and int""elligent model-based controls cannot be generated without itsdevelopment.In the proposed effort here, Colorado State University (C"SU) plans to develop a transient twophaseevaporator model that is experimentally validated. The primary goal of this effort is todevelop a reduced order model for two-phase evaporators that is as general as possible that can beinserted into transient system-lev"el computer simulations for size, weight, and performance(SWaP) design tradeoff studies, while still effectively capturing the phys""ics, including heat transferresistance, thermal capacitance, boiling incipience, and dryout. In addition, during modelvalidation," close integration of two-phase evaporators with fiber-coupled laser diodes will beinvestigated to determine the necessity of developing a custom two-phase heat sink to have asubstantial impact on improving SWaP. This will require a combination of diode characterizationand packaging studies that is based on prior efforts by CSU on similar systems.The proposed effort is intended to support" ongoing efforts by ONR, AFRL, and ARL toinvestigate thermally enabling architectures for pulsed power systems. During the initial"" phase ofthe proposed effort, CSU will be focused on validating the modeling framework with existing testsections, while evaluatin"g various the low thermal resistance options for two-phase evaporatorsusing data on representative fiber-coupled laser diodes. The second phase of the proposed effortwill be focused on gathering additional experimental data for a variety of test fluids in differenttest sections to increase the robustness of the model so that the DOD can use it for design tradeoffstudies and develop intelligent control methods for full thermal systems.SOWTask 1: Two-phase Evaporator Modeling Framework Developmento -Establish Matlab interface requirements for reduced order modelo -Develop initial modeling framework for reduced order modelo -Conduct initial testing of existing structures under transient loado -Validate initial modeling approach for transient loads with existing test sectionsTask 2: Evaluate Evaporator Integration into Fiber-Coupled Diode Packageo -Determine fiber-coupled laser diode wavelength vs. temper"atureo -Integrated PCM, diode, and evaporator modelingo -Investigate close integration of cooling structure and fiber-diodeo -Determ"ine value of microchannel two-phase cooling near fiber-coupled diodesTask 3: Reduced Order Modeling Validation with Two-Phase Heat Sinkso -Select up to 3 COTS and/or custom cold plate solutions to evaluate based on results from Task 2o -Conduct steady-state and transient heat transfer tests with up to 3 candidate fluidso -Update of ROM to incorporate test data and local diode thermal storageo -Use experimental results to validate reduced ord
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 26, 2018
- Source ID
- N000141812198
Entities
People
- Todd Bandhauer
Organizations
- Colorado State University
- Office of Naval Research
- United States Navy