Thermophysical Properties of a Cryogenic Pulsating Heat Pipe

Thermophysical Properties of a Cryogenic Pulsating Heat Pipe

Oscillating (Pulsating) Heat Pipes An OHP consists of a capillary sized tube and a refrigerant. Most OHPs are formed in closed serpentine loops with multiple turns, but OHPs can operate in other configurations Closed End (serpentine but not looped) Open End The tube is evacuated then partially filled with the working fluid Capillary forces create a natural separation of liquid slugs and vapor plugs. Khandekar 04 Operating Regimes Heat flux Static Slug/Plug distribution, generation of small bubbles at high temps. similar to nucleate boiling Critical Heat Flux Oscillatory slug/plug flow develops in individual loops Stable oscillations develop, amplitudes increase with increasing heat flux, and oscillations in multiple tubes come into phase with one another -direction is arbitrary and periodically changes (more so with lower heat flux)

-local oscillations superimposed on system oscillation Annular flow develops in fluid traveling from the evaporator to condenser References 1.Khandekar, S., 2004, Thermo-hydrodynamics of Closed Loop Pulsating Heat Pipes, Institut fur Kernenergetik und Energiesysteme der Universitat Stuttgart. 2.Ma., H. B., Borgmeyer, B., Cheng, P., Zhang, Y., 2008, Heat Transport Capability in an Oscillating Heat Pipe, Journal of Heat Transfer, 130(8), pp. 815011-7. 3.Borgmeyer, B., 2005, Theoretical Analysis and Experimental Investigation of A Pulsating Heat Pipe for Electronics Cooling, Masters Thesis, University of Missouri-Columbia. Modeling OHP modeling has focused on the simpler slug/plug flow regime Multiple modeling approaches have been tried Chaos Continuity, Momentum & Energy Spring-Mass-Damper Non-Dimensional Analysis Artificial Neural Networks Our model has its roots in the spring-mass-damper models presented

by Ma, Borgmeyer, et al.2,3 EES/MATLAB based thermo-hydrodynamic model of an OHP operating in slug-plug flow. d 2 x C dx K B x cos 0 2 dt mtot dt mtot mtot Evaporator Adiabatic Region Condenser . Q Vapor Plug Liquid Slug Tc

The OHP Advantage and Project Goals Advantages OHPs are simpler/lighter than other two-phase heat transfer devices No wick No additional fluid reservoir OHPs may be more robust? Dry-out problems, while not extensively studied, do not appear to be a major problemOHPs may be able to handle higher heat fluxes (convective heat transfer vs. phase change) May be used as a thermal switch Disadvantages Lower effective conductance than Capillary Pumped Loops and Loop Heat Pipes Project Objective: Further the development of the technology/understanding required for successful implementation of an OHP in spacecraft thermal control applications. Approach: theoretical and experimental Deliverable: OHP design guidelines and a physics-based, but semi-empirical, model suitable for design

Recently Viewed Presentations

  • Title of presentation here: Customize the text below Topeka ...

    Title of presentation here: Customize the text below Topeka ...

    Custom-fit solution designed by users and partners. ... KS Health Matters. Kansas Partnership for Improving Community Health (Kan-PICH) ... Evaluation and Tracking (Healthy People 2020) Learn about important issues . Identify possible improvements.
  • NTMs Classification, ATR and NTRs in the Context of ATIGA's ...

    NTMs Classification, ATR and NTRs in the Context of ATIGA's ...

    Indicate year of notification to ASEAN Secretariat. Proposed NTM Classification Template. ... 9 of the new Agriculture Standard requires that frozen chicken be displayed in proper freezers that allow cool air to pass regularly to all parts of the frozen...
  • Benue State University 10th Innaugural Lecture

    Benue State University 10th Innaugural Lecture

    benue state university 10th innaugural lecture. titled:the dilemma of the science teacher in the implementaiton of science education curriculum reforms at the basic education level in nigeria
  • Islamic Agricultural & Rural Finance Muhammad Zubair Mughal

    Islamic Agricultural & Rural Finance Muhammad Zubair Mughal

    A pre-delivery financing instrument used to finance projects where commodity is transacted before it comes into existence. It is an order to manufacture and payment of price, unlike Salam, it's flexible, where price may be paid in advance, or in...
  • Chapter 15 Integrated Services Digital Network ISDN

    Chapter 15 Integrated Services Digital Network ISDN

    Chapter 15 Integrated Services Digital Network ISDN Services History Subscriber Access Layers BISDN Figure 15-1 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 ISDN Services Figure 15-2 WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998 Voice over Analog Network Figure 15-3 WCB/McGraw ...
  • Welcome to Class St Margaret Year 6 - st-francis.kent.sch.uk

    Welcome to Class St Margaret Year 6 - st-francis.kent.sch.uk

    Welcome to St Paul & St Peter Year 4 Class Teachers: Mrs. Hawkes & Mrs Zokra Teaching Assistants: Mrs Duran & Mrs Martin What you need to know… Equipment and water bottles PE kits and uniform Homework/home learning Support for...
  • Uni-Gold™ Training Session

    Uni-Gold™ Training Session

    Uni-Gold™ HIV Fingerstick Procedure Uni-Gold™ HIV Fingerstick Procedure Uni-Gold™ HIV Fingerstick Procedure Uni-Gold™ HIV Fingerstick Procedure Uni-Gold™ HIV Fingerstick Procedure Control Line Area Uni-Gold™ HIV Fingerstick Procedure Uni-Gold™ HIV Fingerstick Procedure Invalid Results #1 Invalid - Sample port without full...
  • SPECIAL COMMITTEE ON INTERMODAL TRANSPORTATION & ECONOMIC EXPANSION

    SPECIAL COMMITTEE ON INTERMODAL TRANSPORTATION & ECONOMIC EXPANSION

    MS Freight System at a Glance. A diversity of freight moves through our transportation system that encompasses all modes. Our multimodal freight network includes coastal and river ports, highways, Class I and short line railroads, airports, intermodal facilities and pipelines.