The Constrained Vapor Bubble Experiment for ISS – Earth's Gravity Results

The constrained vapor bubble (CVB) experiment is one of the significant investigations into fluid physics in microgravity conditions being undertaken by NASA. Destined to fly on the International Space Station by the end of 2009, the experiment will yield data that will provide new insight into the complex phenomena occurring in systems such as nucleate boiling and heat pipes. It will consist of a transparent heat pipe made from quartz using pentane as working fluid with an extraordinary level of instrumentation allowing us, for the first time, to study every aspect of the heat pipe in great detail. Earth's gravity based data was collected at NASA Glenn using an identical hardware to that from the ISS. This data will be compared with the space based data to better understand how the interfacial forces are affected in the microgravity environment where the Bond number will be very small. Here we present earth's gravity environment data and try to match it with predictions from a theoretical model. The model uses the Young-Laplace equation to calculate the fluid pressure gradient and solves the momentum equation in the liquid and vapor phases. It also takes into account the heat conduction in the solid quartz and calculates the temperature profile along the heat pipe device which can be matched with the experimental data. Predictions will also be made about how the heat pipe device is expected to behave in space.