Heat Flux in Low Mass Flux Horizontal Cryogenic Flow

Liquid hydrogen (LH2) is the highest specific impulse rocket fuel commonly available. However, launch systems using LH2 are informed by flow boiling heat transfer and pressure drop correlations, the most recent of which has up to 50% root-mean-squared error. This error is exacerbated because no previous experiments have optically verified cryogenic multiphase flow regimes concurrent with heat transfer measurements in pipes with diameter larger than 14.1 mm. To address this gap, this thesis presents the development of a two-phase hydrogen flow cell that can address uncertainty in existing models by providing temperature, velocity, and pressure drop data while visually identifying flow regimes. Results using liquid nitrogen are provided with comparison to recent flow boiling correlations for heat transfer coefficient, pressure, quality, and velocity. Recommendations are made for correlation modification with demonstrated predictive improvement.