NASA - National Aeronautics and Space Administration

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Experiment/Payload Overview

Brief Summary

Boiling efficiently removes large amounts of heat by generating vapor from liquid; this process is currently being used in many power plants to generate electricity. An upper limit, called the critical heat flux, exists where the heater is covered with so much vapor that liquid supply to the heater begins to decrease, potentially destroying the heater. Microheater Array Boiling Experiment (MABE) determines the critical heat flux during boiling in microgravity to design optimal cooling systems for future space exploration vehicles as well as on Earth.

Principal Investigator

Jungho Kim, Ph.D., University of Maryland, College Park, College Park, MD, United States

Co-Investigator(s)/Collaborator(s)

John McQuillen, , Glenn Research Center, Cleveland, OH, United States

Payload Developer

Glenn Research Center, Cleveland, OH, United States

Sponsoring Space Agency

National Aeronautics and Space Administration (NASA)

Sponsoring Organization:

Exploration Systems Mission Directorate (ESMD)

ISS Expedition Duration:

September 2010 - March 2011

Expeditions Assigned

25/26

Previous ISS Missions

MABE is a unique investigation, nothing like this has flown in space before. It measures local heat transfer coefficient with finer temporal and spatial fidelity than any previous pool boiling experiment.

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Experiment/Payload Description

Research Summary

• Microheater Array Boiling Experiment (MABE) is one of two investigations scheduled to operate in the Boiling eXperiment Facility (BXF). The other investigation is Nucleate Pool Boiling Experiment (NPBX).



• Understanding of microgravity effects on boiling mechanisms is critical to the proper design of heat removal equipment for use in space-based applications.

Description

Boiling heat transfer is a method whereby large amounts of heat can be removed from a material. This process is being used in electric power plants, electronic cooling and purification and separation of chemical mixtures. An upper limit, called the critical heat flux, exists where the heater is covered with so much vapor that liquid supply to the heater begins to decrease. Supplying constant power above this limit for prolonged periods can increase the heater temperature to the point whereby the heater is destroyed. Determination of critical heat flux in microgravity is essential for designing cooling systems for space. In this experiment, scientists study boiling of fluorocarbons to increase the effectiveness of cooling in space.

Boiling of n-perfluorohexane is studied in MABE. n-perfluorohexane is the main ingredient in FC-72. FC-72 is used by the electronic industry for cooling and by a wide cadre of boiling researchers because of its inertness, low boiling point and low heat of vaporization.

The Boiling eXperiment Facility (BXF) houses two separate investigations, Microheater Array Boiling Experiment (MABE) and Nucleate Pool Boiling Experiment (NPBX). BXF is planned for the Microgravity Science Glovebox (MSG) located in the US Lab on the International Space Station (ISS). The purpose of the BXF is to validate models being developed for heat transfer coefficients, critical heat flux and pool boiling curves.

BXF-MABE provides localized, time-dependent, heat transfer coefficients that will be correlated against known positions of vapor and liquid above the heater array to determine the mechanisms by which heat is removed through boiling in the absence of gravity.

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Applications

Space Applications

In microgravity, a bubble can cover an entire heater array instead of just a small area, resulting in burnout of components if local hot spots are present. The increased spatial resolution of these measurements will enable the extent of the dry spot to be measured along with the heat transfer from the liquid surrounding the dry spot. This technique can be applied to other areas including spray cooling, turbulence measurements and flow boiling.

Earth Applications

The proposed research has shown that transient conduction is the dominant heat transfer mechanism in boiling of refrigerants-like fluids. This research will provide insight into creating more efficient cooling systems on Earth.

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Operations

Operational Requirements

MABE utilizes two heater arrays ( (7 mm x 7 mm and 2.7 mm x 2.7 mm), each heater array consisting of 96 individually controlled heaters. The heaters are operated at a constant temperature, enabling measurements to be made at critical heat flux and beyond. A group of experiments is run with each microheater array. Each group contains a set of individual experiments with the initial starting point at a specific bulk fluid temperature and pressure. For each experiment, the temperature of the selected microheater array is increased to the desired temperature and the heat transfer distribution during boiling is measured. During the experiments, video is recorded using the MSG cameras and stored on a hard drive. If Ku band is available, video data will be downlinked from ISS to the Glenn Research Center TeleScience Center in Cleveland, OH. The heater data will be overlaid onto the high-speed video data to correlate vapor and liquid position on the heater array. These results will be used to validate and test theoretical models of boiling mechanisms.

MABE will require crew time to set up the hardware to perform 40 test sessions. The data from the test sessions will be captured on videotapes and hard drives that will be changed out by the crew. The hard drive and videotapes will be stowed for later return to Earth for analysis by the investigator.

Operational Protocols

This investigation requires the crew to set up the BXF hardware in the Microgravity Science Glovebox. Once activated, a ground-based crew controls the BXF. BXF-MABE runs for 28 hours and performs a total of 40 test sessions. The crew performs hard drive and videotape changes at specific intervals throughout the sessions. After the session is completed the crew deactivates, labels and stows the BXF hardware.

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Results/More Information

Information Pending

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Related Web Sites

ISS Research Project-BXF-MABE

Boiling in Microgravity

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Publications

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Ground Based Results Publications

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ISS Patent Publications

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Related Publications

• Myers J G,Yerrramilli V K,Hussey S W,Yee G F,Kim J ,Time and space resolved wall temperature and heat flux measurements during nucleate boiling with constant heat flux boundary conditions International Journal of Heat and Mass Transfer 2005 48 2429-2442
• Henry C D,Kim J ,Chamberlain B ,Hartmann T G,Heater aspect ratio effects on pool boiling heat transfer under varying gravity conditions Experimental Thermal and Fluid Science 2005 29 773-782
• Yin Z ,Prosperetti A ,Kim J ,Bubble Growth on an Impulsively Powered Microheater International Journal of Heat and Mass Transfer 2004 47 1053-1067
• Henry C D,Kim J ,Heater size, subcooling, and gravity effects on pool boiling heat transfer International Journal of Heat and Fluid Flow 2004 25 262-273
• Demiray F ,Kim J ,Microscale Heat Transfer Measurements During Pool Boiling of FC-72: Effect of Subcooling International Journal of Heat and Mass Transfer 2004 47 3257-3268
• Henry C D,Kim J ,Thermocapillary Effects on Low-G Pool Boiling From Microheater Arrays of Various Aspect Ratio Microgravity Science and Technology 2005 16 170-175
• Henry C D,Kim J ,McQuillen J ,Dissolved Gas Effects on Thermocapillary Convection During Boiling in Reduced Gravity Environments Heat and Mass Transfer 2006 42 919-928
• Kim J ,McQuillen J ,Balombin J ,Microheater Array Boiling Experiment NASA TM 2002

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Images

Image of liquid boiling on a heater array during the low gravity produced by NASA's KC-135 aircraft. Blue regions indicate regions of low heat transfer. Courtesy of University of Maryland.

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