In the present paper, an experimental investigation of the humidifying and desulfuration of flue gas by water spraying is conducted in order to increase the ability of the self-desulfuration efficiency of Ca composition in coal in a power plant boiler. The experimental facility, nozzle structure, measurement method and instruments are introduced. The influence of nozzle structure, the way to enter the liquid and the ratio between phases on the spray characteristics including size distribution of the droplet and spray angle is studied. The results show significant variation and show how to optimize the design and operation of the nozzles.

Experiments for subcooled water flow and for steam-water two-phase flow were conducted to investigate the effects of pulsation upon transient heat transfer characteristics in a closed-circulation helical-coiled tube steam generator. The non-uniform property of local heat transfer with steady flow was examined. The secondary flow and the effect of interaction between the flow oscillation and secondary flow were analyzed on basis of the experimental data. Some new phenomena were observed and explained. Correlations were proposed for average and local heat transfer coefficients both under steady and oscillatory flow conditions. The results showed that there exist considerable variations in local and peripherally time-averaged Nusselt numbers for pulsating flow. Investigations of pressure drop type oscillations and their thresholds for steam-water two-phase flow in a uniformly heated helical tube were also reported.

Experiments were conducted to investigate the effects of pulsation upon transient heat transfer characteristics for fully-developed turbulent flow in a uniformly heated helical coiled tube. The non-uniform feather of local heat transfer with steady flow was also examined. The secondary flow mechanism and the effect of interaction between the flow oscillation and secondary flow were analyzed on the basis of the experimental data. Some new phenomena were observed and explained. A series of correlations were proposed for the average and local heat transfer coefficients both under steady and oscillatory flow conditions. The results showed that there were considerable variations in local and peripherally timeaverage Nusselt numbers for pulsating flow in a wide range of parameters.

Systematic investigations of pressure drop type oscillations and their thresholds were conducted for steam-water two-phase flow in a uniformly heated, helically coiled tube. Experiments were conducted to obtain the critical conditions for the occurrence of pressure drop type dynamic oscillation in a closed-circulation helically coiled tubing steam generator. The study showed that different locations of the tank which provided a compressible gas volume (called compressible volume for short) corresponded to different oscillation initial boundaries as well as different oscillating amplitudes and time periods. Moving compressible volume from the inlet of the steam generator upstream could dramatically suppress the occurrence of pressure drop oscillation. Also, non-uniform heat flux distribution along the evaporating channel could change oscillating boundaries significantly, especially when higher heat flux was applied to the higher mass quality region. A study of pressure drop oscillation in various steam generator inclinations showed that gravity has little influence upon the oscillating boundaries. Based on the experimental observations, a set of new methods was first proposed to eliminate the occurrence of pressure drop oscillation.

Experimental investigations on oil-air-water three-phase flow were carried out in two helically coiled tubes with inner diameter of 39mm and coil diameters of 265 and 522.5mm, respectively. The purpose of this work is to provide a basis for the invention and development of a new kind of separation technology for gas-oil-water mixtures with low oil fraction β≤30%. The flow patterns of oil-water two-phase flow and oil-air-water three-phase flow were directly observed in test sections made of plexiglass tubes. The flows observed in coiled tubes could be classified into more than four flow patterns and some flow regime maps were generated and delineated for these tubes. The present results were compared with some results in horizontal flow. The phase inversion characteristics in helically coiled tubes were also discussed. The frictional pressure drop of oil-air-water three-phase flow were measured. The effects of flow rates and liquid properties on pressure drop were examined. Based on the experimental data and analysis of the flow mechanism the criteria for the flow pattern transition boundaries between two different flow patterns were proposed in terms of dimensionless parameters. Correlations for the predictions of pressure drop were also obtained.