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Abstract: Drag enhancement is reported for turbulent pipe flow of aqueous electrolyte solutions. No electroviscous effect was obtained with laminar flow. Nor was any unusual pressure drop observed for laminar or turbulent flow of non-electrolyte aqueous solutions such as sugar. An electroviscous theory was advanced that predicted the drag enhancement for a 1/1 electrolyte solution. The theory depended on consideration of Debye length. [Copyright &y& Elsevier]

Abstract: Three phase water/oil/air flow was studied around a vertical upward to horizontal 90° elbow bend of R/d =0.654. The results were more complex than corresponding two phase data. The pressure drop recorded for the two tangent legs sometimes showed significant variations to the straight pipe data. In most cases this variation was caused by differences in the flow regimes between the two systems. The elbow bend tended to constrict the flow presented by the vertical inlet tangent leg while sometimes acting as a wave and droplet generator for the horizontal outlet tangent leg. It could be argued that the inclusion of the elbow bend altered the flow regime map transitional boundaries but it also is possible that insufficient settling length was provided in the apparatus design. The elbow bend pressure drop was best presented as l e/d the equivalent length to diameter ratio using the actual total pressure drop in the vertical inlet tangent leg. Generally l e/d values rose with gas rate, but exhibited an increasingly complex relation with f o the oil to liquid volumetric ratio as liquid rate was increased. A significant maximum in l e/d was in evidence around the inversion from water dominated to oil dominated flows. Several models are presented to predict the data. [Copyright &y& Elsevier]

Abstract: Pressure drop data are reported for two phase air–water flow through a vertical to horizontal 90° elbow bend set in 0.026m i.d. pipe. The pressure drop in the vertical inlet tangent showed some significant differences to that found for straight vertical pipe. This was caused by the elbow bend partially choking the inflow resulting in a build-up of pressure and liquid in the vertical inlet riser and differences in the structure of the flow regimes when compared to the straight vertical pipe. The horizontal outlet tangent by contrast gave data in general agreement with literature even to exhibiting a drag reduction region at low liquid rates and gas velocities between 1 and 2ms−1. The elbow bend pressure drop was best correlated in terms of l e/d determined using the actual pressure loss in the inlet vertical riser. The data showed a general increase with fluid rates that tapered off at high fluid rates and exhibited a negative pressure region at low rates. The latter was attributed to the flow being smoothly accommodated by the bend when it passed from slug flow in the riser to smooth stratified flow in the outlet tangent. A general correlation was presented for the elbow bend pressure drop in terms of total Reynolds numbers. A modified Lockhart–Martinelli model gave prediction of the data. [Copyright &y& Elsevier]

Abstract: Empirical correlations were tested against reliable two phase pipe flow data for the prediction of pressure drop. Correlations are recommended for the prediction with stratified and annular type flows. When these correlations were adapted to three phase gas–water–oil pipe flow in general they predicted for intermittent slug type flows. Momentum balance models could not be successfully adapted to the prediction of pipe three phase pressure drop. [Copyright &y& Elsevier]

Abstract: A wide range of experimental results carried out in low enthalpy facilities is used to sustain simple correlations predicting heat transfer rates on an attachment line in hypersonic flow. It is observed that for long swept cylinders a nearly asymptotic state can be reached for which transition Reynolds number does not change substantially quite far from the apex of the cylinder. Intermittency based on measured heat fluxes was used to describe the laminar–turbulent process. Prediction of turbulent heat transfer rates is established using a reference temperature method that provides quick and relatively accurate estimates for a wide range of Mach number and temperature ratio. [Copyright &y& Elsevier]