Laser-based measurements of two-phase flashing propane jets.

Two-phase flows hold an interest in many areas of science and engineering. In the safety field, one such topic is the accidental release of flammable and toxic pressure-liquefied gases (PLGs) such as propane and chlorine, which may result in great loss of life and material losses. Of specific interest in this area are the mathematical models and predictive computer codes which may be applied to such releases in order to inform risk assessment on transport, storage and accidental release scenarios in land use planning. Currently such models can only accurately predict the behaviour of the later stages of accidental releases of pressure liquefied gases and there is a little experimental data against which to validate near-field models. A facility has been designed and constructed to allow the safe study, by non-intrusive techniques, of two-phase flashing propane jets; propane (and LPG) being involved in the majority of major industrial two-phase accidental releases resulting in loss of life. Each jet release has been characterised by the measurement of its mass release rate, and temperature and pressure parameters at storage and exit positions. Liquid phase velocity and size distributions have been measured in the near-field regions using Laser Doppler Anemometry (LDA) and a diffraction-based sizer respectively. Various data manipulation techniques have been applied to the raw data in order to obtain the best quality results from the measurements. Centreline and lateral profiles of the velocity and droplet size parameters are presented, along with conventionally measured liquid temperature centreline and lateral profiles. The data generated can be used to evaluate and develop predictive mathematical models, and comparison with certain models is presented. A technique has also been developed for the non-intrusive measurement of liquid propane temperature in a two-phase flashing jet scenario, and its suitability confirmed and calibrated. Overall, a body of data has been produced, and made available, for a two-phase flashing propane jet, improving upon the little that previously existed.