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An experimental study to investigate the transient processes which occur when hot liquid spray droplets are suddenly injected into a gas contained in a closed chamber was reported previously [Proc. Inst. Mech. Eng. 215E (2001) 79]. That work also presented a macroscopic (bulk) analysis model, which agreed reasonably well with the experimental data. This work presents an analysis based on the simultaneous solution of the energy and mass balance equations for a single droplet and the gas-vapour control volume associated with the droplet. Good agreement has been found between the experimental data and the results of the single droplet analysis. The values of the heat transfer Nusselt number and the mass transfer Sherwood number, found using this approach, are approximately equal to 1. This agrees well with the results obtained from the macroscopic analysis reported previously and studies on heat transfer from dense evaporative droplet sprays.

A numerical study has been undertaken to examine the behaviour of a gas liquid interface in a vertical cylindrical vessel subjected to a sinusoidal vertical motion. The computational method used is based on the simplified marker-and-cell method and includes a continuum surface model for the incorporation of surface tension. The numerical results indicate that the surface tension has very little effect on the period and amplitude of oscillations of the interfacial waves. The stability of the interfacial waves has been found to depend on the initial pressure pulse disturbance, and exponential growth of the interfacial wave has been observed in some cases. The influence of the amplitude and frequency of the forcing oscillations has also been investigated. The results are in good agreement with available experimental and analytical solutions.

An experimental and theoretical study has been made to investigate the transient processes which occur when hot liquid spray droplets are suddenly injected into a gas contained in a closed chamber. A novel experimental apparatus was employed in which hot water is injected via commercial solid cone spray nozzles into air enclosed in a cylindrical spray chamber, of 121 mm diameter and 190 mm height, at a pre-determined constant flowrate, and for a set duration, under computer control. Measurements were made of the spray chamber pressure rise with time due to the combined effects of liquid—gas heat transfer, droplet evaporation and liquid accumulation in the chamber. The experimental results reported in the paper cover a range of nozzle sizes, in both single-nozzle and multi-nozzle configurations, and the effects of liquid flowrate, initial gas pressure and initial liquid—gas temperature difference are considered. A simple analytical model has been developed which subdivides the chamber volume into three zones: a liquid zone, a transfer zone where heat and mass transfer occurs, defined by the spray cone angle, and a still zone outside the spray cone. The analysis gathers the important parameters governing droplet heat transfer in a single dimensionless group, denoted by K2. For the range of conditions investigated, reasonable agreement between the experimental results and the theoretical solutions were obtained with a value of K2 = 2 × 10−5.

An investigation has been undertaken to examine the stability of a gas-liquid interface in a vertical cylindrical vessel subjected to a sinusoidal vertical motion. Experimental results indicate that there is a certain limiting critical frequency at which the gas-liquid interface becomes unstable, significant amounts of liquid are thrown vertically from the interface and the interface thus loses its coherent structure. Experimental data are compared with analytical solution based on the reduction of governing non-viscous equations to Mathieu equation, and good agreement between theory and experiment is found.

This work is concerned with the description of an experimental rig based around a constant volume spray chamber, and its data acquisition and control system. A testing rig was designed to deliver a spray through one or multiple spray nozzles into a constant volume spray chamber. The delivery system had a syringe, or cylinder and piston, like arrangement, enabling injection of water at a predetermined temperature and flowrate. A sophisticated data acquisition and control system was employed, that enabled transient measurements of pressure and temperature upstream the nozzle and pressure change inside the spray chamber.

This paper deals with the generation and the movement of the liquid phase in the last stages of large condensing steam turbines. Considering thermodynamic instability, the primary droplet size resulting from spontaneous condensation is dependent on radial position, the flow, and inlet parameters. The analysis of the liquid phase transport to the blade surface is given, and the stability and disintegration of the liquid films on the blade surface is discussed.