Constrained Vapor Bubble (CVB)

Science Objectives

Constrained Vapor Bubble (CVB) aims to achieve a better understanding of the physics of evaporation and condensation and how they affect cooling processes in microgravity using a remotely controlled microscope and a small cooling device.

Status

The experiment has concluded, and science is being evaluated.

Astronaut with his hand inside large, white latex gloves attached to a gold, mechanical device.

NASA astronaut T. J. Creamer performs operations with the Constrained Vapor Bubble (CVB) Module on the Light Microscopy Module (LMM).

A row of small blue and white circles within a clear tube.

Photograph taken during the inspection of the CVB (Constrained Vapor Bubble) module with the science sample on the FIR (Fluids Integrated Rack). Photo taken by the Expedition 20 crew.

A metallic rectangular device with a blue nob on the side with a silver nob underneath it. In the center, is a glass opening showing a small white, orange and black rectangular device inside.

Stowage hardware from Kennedy Space Center (KSC) Bench Review (BR) #2, held on April 29, 2009. This image set contains contents of M-Bags stowed on the Multi-Purpose Logistics Module (MPLM) Forward and Aft Bay 2 Resupply Stowage Platform (RSP) front sides. MPL1F2_A1: Constrained Vapor Bubble (CVB)

Experiment Description

The thermophysical principles underlying change-of-phase heat transfer systems are not well understood in microgravity conditions and are less than optimized even in earth gravity. This experiment proposes basic experimental and theoretical studies of the nonisothermal Constrained Vapor Bubble (CVB) under microgravity conditions. The CVB represents a passive, wickless heat pipe ideally suited to obtain engineering and fundamental data on phase change heat transfer driven by interfacial phenomena. The proposed study represents a basic scientific study in interfacial phenomena, microgravity fluid physics and thermodynamics, a basic study in thermal transport and an engineering study of a passive heat exchanger. This optical study of vapor bubbles constrained in transparent glass cells at variable temperature increases the basic understanding of heat and mass transfer at phase-change interfaces. The information obtained from the study optimizes the design and operation of passive heat transfer devices for earth and microgravity environments and is critically important for the successful completion of long-term lunar and Mars missions.

Space Applications

CVB has performed ground-based studies in a thermal vacuum chamber to determine the efficiency of the heater and cooler configuration. Large thermal response times that have been experimentally observed in space-based experiments cannot be obtained from these ground-based studies. Space-based experimentation is the only method available to ascertain internal low-gravity fluid mechanics within a heat pipe.

Earth Applications

The project aims to achieve an improved understanding of microscale heat transfer, improved designs for wickless heat pipes, and an increased efficiency in heat transfer devices for cooling critical components. Targeted users are existing microelectronics industry and perhaps military applications. New designs should be able to be developed several months following the analysis and presentation of the results from the experiment.