Dziubinski

Dziubinski, M. and Richardson, J. F. J. Pipelines 5 (1985) 107. Two-phase flow of gas and non-Newtonian liquids in horizontal pipes — superficial velocity for maximum power saving. 

Kemblowski, Z., DZIUBINSKI, M. and Mertl, J. Adv. in Transport Proc. 5 (1987) 117. Flow of non-Newtonian fluids through granular media. 

It may be noted that energy will be required for compressing the mr to the injection pressure which must exceed the upstream pressure in the pipeline. The conditions under which power-saving is achieved have been examined by DZIUBINSKI V who has shown that the relative efficiency of the liquid pump and the air compressor are critically important factors. 

Dziubinski, M. Fratczak, M. 2006. Aspects of risk analysis associated with major failures of fuel pipelines. Journal of Loss Prevention in the Process Industries 19(5) 399 8. 

In a recent study, Dziubinski [1995] has put forward an alternative formulation for the prediction of the two-phase pressure drop for a gas and shear-thinning liquid mixture in the intermittent flow regime. By analogy with... 

For power-law fluids in streamline flow, Dziubinski s expression for the drag ratio is ... 

Attention is drawn to the fact that the values of m and n for use in turbulent region are deduced from the data in the laminar range at the values of (SVp/D) which is only the nominal shear rate at the tube wall for streamline flow, and thus this aspect of the procedure is completely empirical. Dziubinski [1995] stated that equation (4.26) reproduced the same experimental data as those referred to earlier with an average error of 15%, while equation (4.28) correlated the turbulent flow data with an error of 25%. Notwithstanding the marginal improvement over the method of Dziubinski and Chhabra [1989], it is reiterated here that both methods are of an entirely empirical nature and therefore the extrapolation beyond the range of experimental conditions must be treated with reserve. 

However, additional energy will be required to compress the air to a pressure in excess of the upstream pressure. Thus, the circumstances under which there will be a net saving of power for pmnping will be strongly dependent on the relative elficiences of the slurry pirnip and the gas compressor, and on the specific plant layout. Dziubinski and Richardson [1985] have addressed this problem and the salient features of their study are siunmarised here. They introduced a power saving coefficient, defined as... 

However, for the relative efficiences of the slurry pump and the compressor in the ratio of 1 to 2, the approach of Dziubinski and Richardson [1985] yields the optimum gas velocity to be 0.2 m/s, which is much smaUar than the value of 2.86m/s for maximum drag reduction. 

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