An experimental investigation on high‐viscosity oil‐water flow in a horizontal pipe (I.D. = 26 mm) has been conducted. The oil viscosity investigated varied between 3800 and 16 000 mPa · s. Flow patterns observed in experiments are presented and flow pattern maps are reported. The inversion from oil‐continuous to annular‐water‐continuous is discussed. The average pressure gradient of oil‐continuous two‐phase flow can be reduced before the inversion to annular‐water‐continuous flow due to partial lubrication from discontinuous water streams. The stable water‐lubricated flow develops at a lower input water volume fraction with increase of the superficial oil velocity. An empirical criterion for the formation of stable water‐lubricated flow was proposed in terms of the oil phase Froude number and the input water volume fraction. The friction factor of water‐lubricated flow can be one to two orders of magnitude higher than that of single‐phase water flow and has a faster decrease with increase of the Reynolds number than that of single‐phase turbulent flow. These are linked to the oil fouling on the pipe wall. Models for the prediction of the pressure gradient of core flow proposed by different authors in the literature were evaluated with the experimental data.

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In this paper, the thermal performance of residential building envelopes including thermal bridges (TBs) in a hot climate, using four different exterior wall types, is modelled and assessed. TBs at the junctions between columns and walls and between walls and slabs of the ground floor, roof, and intermediate floors are considered. The tested wall types are classical (two layers of cement blocks with insulation in between), autoclaved aerated concrete bearing (AAC-B), AAC column and beam (AAC-CB), and exterior insulation and finish system (EIFS). The results indicated that thermal bridges have a considerable effect and determine the best external wall type which was the EIFS that has a continuous exterior insulation. EIFS proved to reduce the heat transmission with the outdoor environment for residential buildings by 101.8, 51.2, and 13.9% than the AAC-CB, AAC-B, and classical walls, respectively. Thermal bridges effect on the building envelope using the EIFS is insignificant as the thermal resistance of the envelope and wall differs by less than 1% for small areas. The overall heat transfer coefficients for small buildings are larger than those for large buildings by 8–26%. As the number of intermediate floors increases from 1 to 50, the envelope overall heat transfer coefficient increases by 4.5% for the EIFS, 14.1% for classical, and 19.5% for AAC-CB walls. The AAC-CB, as the common practice wall structure in many hot climate countries, has the lowest performance among the tested wall types.

This paper investigates the effect of heat transfer on the motion of a spherical bubble in the vicinity of a rigid boundary. The effects of heat transfer between the bubble and the surrounding fluid, and the resulting loss of energy from the bubble, can be incorporated into the simple spherical bubble model with the addition of a single extra ordinary differential equation. The numerical results show that for a bubble close to an infinite rigid boundary there are significant differences in both the radius and Kelvin impulse of the bubble when the heat transfer effects are included.

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