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Correlations were developed to predict total and dynamic liquid holdup in terms of drift flux model, hold up ratio, and gas and liquid Reynolds numbers for the experimental data of the present study covering air-water and air-MEA systems for three different packing and a wide range of literature data. These corelations predict the present data and most of the literature data with an RMS deviation less than 0.1. The present static liquid holdup data was found to agree with the correlation due to Saez and Carbonell (1985).

Bubble flow, pulse flow and spray flow are the identified flow regimes for cocurrent upflow of air and water through a bed of ceramic spheres. Criteria for transition from one regime to another are presented. Pressure drop for the two phase flow is experimentally measured and the two phase friction factor is correlated as f = KRe(g)mRe1(-n) (d(p)/d(c))1.5 where (m, n) are respectively (0.18, 1.7), (0.26, 1.7) and (1.12, 1.82) corresponding to bubble flow, pulse flow and spray flow regimes.

Alloying element vaporization rates, plasma composition, and the changes in weld composition during laser welding of 202 stainless steel are discussed in this paper. Iron, manganese, and chromium were the most dominant species in the plasma. During laser welding it is always a difficult task to measure the temperature of the weld pool since this region is surrounded by hot plasma. In this paper a novel technique for the determination of weld pool temperature is presented. It is demonstrated that the relative rates of vaporization of any two elements from the molten pool can serve as an indicator of weld pool temperature, irrespective of the element pair selected. The composition of the solidified region calculated from the measured values of vaporization rate, plasma composition, and the volume of the solidified region was in good agreement with the weld composition determined by electron probe microanalyis technique.

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