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News, features & press releases



The proposed research aims to develop an integrated two-phase flow boiling/condensation facility for the International Space Station (ISS) to serve as a primary platform for obtaining two-phase flow and heat transfer data in microgravity. By comparing the microgravity data against those obtained in Earth’s gravity, it will be possible to ascertain the influence of body force on two-phase transport phenomena in pursuit of mechanistic models as well as correlations, and to help determine the minimum flow criteria to ensure gravity independent flow boiling and condensation. This research will be a joint effort between the Purdue University Boiling and Two-Phase Flow Laboratory (BTPFL) and the NASA Glenn Research Center. Personnel from the two organizations combine extensive experience in research and development of both flow boiling and condensation systems, and in conducting microgravity experiments.


• Obtain flow boiling database in a long-duration microgravity environment

• Obtain flow condensation database in a long-duration microgravity environment

• Develop an experimentally validated, mechanistic model for microgravity flow boiling critical heat flux (CHF) and dimensionless criteria to predict minimum flow velocity required to ensure gravity-independent CHF

• Develop an experimentally validated, mechanistic model for microgravity annular condensation and dimensionless criteria to predict minimum flow velocity required to ensure gravity-independent annular condensation; also develop correlations for other condensation regimes in microgravity


• Reduced gravity condensation and flow boiling heat transfer data and models are virtually nonexistent.

• Long-duration space missions will demand additional power and heat dissipation requirements compared to current space missions. To reduce size and weight, the transition from single-phase to two-phase thermal management systems is necessary.

• In addition, two-phase thermal management systems are more effective heat transfer systems compared to single-phase systems because two-phase systems rely on latent heat exchange rather than sensible heat exchange.

• Flow boiling and condensation data in microgravity are also needed to validate numerical simulation tools that could be used to design space-based two-phase thermal management systems.


• Develop two-phase flow loop to condition dielectric coolant FC-72 (or normal perfluorohexane (C6F14), pure constituent in FC-72) to preset values of flow rate, pressure, and temperature to the test module

• Develop Flow Boiling Module (FBM) to study subcooled and saturated flow boiling and critical heat flux (CHF)

• Develop two separate Condensation Modules to enable study of condensation flow and heat transfer regimes: Condensation Module (CM1) for heat transfer measurements and Condensation Module (CM2) for flow visualization


• Feb 2014 – FBCE held its Requirements Definition Review (RDR) and it consisted of both a science panel and engineering panel. The RDR Science Panel re-affirmed that FBCE has substantial value to the multiphase heat transfer community. They also stated that “Extensive ground and parabolic flight testing have been completed that validate the experimental concept. The project is sufficiently mature to move forward toward space deployment.” Similarly, the two technology advisors affirmed that FBCE “is necessary for gathering multiphase data critical to the development of thermal control and power technology for larger and longer duration space missions..” The engineering panel commented that “The science and engineering teams have done an excellent job in defining and conducting the ground experiments, and providing confidence in the overall design approach for the ISS experiments.”

• Sept 2013 – Two aircraft rigs that supported FBCE flew during the GRC aircraft flight campaign the week of Sept 17 at Ellington Field in Houston, TX. Reduced Gravity Aircraft Testing was conducted by GRC personnel using GRC’s Flow Boiling Module (FBM) Rig. The FBM rig was tested and showed excellent performance in repeatability in vapor production. The Carthage College “Degassing FC-72 in Microgravity” aircraft rig was given the opportunity to fly again. The central objective for the FC-72 de-gassing experiment was to provide comparative data for filtration efficiency of a radial membrane contactor in reduced gravity for use in de-gassing liquid FC-72.

• Dec 2012 – FBCE held an Informal Design Review whose purpose was to present the current status of the design to an engineering panel and to get an assessment of the state of the FBCE design in meeting the science requirements for the Requirements Definition Review (RDR). Numerous comments were made by the panel members covers the fluid system, thermal, avionics, software and imaging which the FBCE team will incorporate as they progress with the hardware testing and build.

• Nov 2011 – FBCE received its authority to proceed from NASA HQ following a successfully Science Requirements Review. The science panel commented that “the Flow Boiling and Condensation Experiment (FBCE) has substantial value to the multiphase heat transfer community, and there exists a compelling need to utilize the international space station for a high quality, long duration microgravity environment in order to meet the project scientific objectives.” The two technology advisors present during the review commented that FBCE “is maturing towards being a platform that will provide vital scientific validation for mechanistic models necessary for design of microgravity two-phase thermal and power systems” and “two-phase fluid transport systems offer much improved energy-to-mass ratios compared to single-phase system, but data and models for reduced gravity flow boiling and condensation are essentially non-existent”. These are areas where FBCE can make significant contributions. Several recommendations were also made by the science panels and will be reviewed and address prior to the next major review.



Contacts at NASA Glenn Research Center
Project Manager:  Nancy Rebel Hall, NASA GRC
Project Scientist:  David Chao, NASA GRC
Principal Investigator:  Issam Mudawar, Purdue University
Co-Principal Investigator:  Mohammad Mojibul Hasan, NASA GRC

Engineering Team: GRC Engineering