A capillary tube is widely used as an expansion device for small refrigeration cycles. Recently, immiscible oil is sometimes used in the refrigeration cycle to improve severe lubricating conditions and to prevent blockage of the capillary tube caused by the hydrolysis of ester oil. This paper discusses the influence of mixing of the immiscible oil with the refrigerant on the flow characteristic...

In the present work, the critical heat flux measurements were performed for the subcooled flow boiling of pure water and magnetic nanofluids (i.e., water + 0.01 and 0.1 vol.% Fe‌‌3O4) in a vertical tube. The effect of applying an external magnetic field on the CHF variation was studied experimentally as well. The obtained results indicated that the subcooled flow boiling CHF in the vertical tub...

Selection of spiral capillary tube for refrigeration appliances and the effect of changes in the parameters such as capillary tube dimensions i.e. capillary tube diameter, coil pitch, capillary tube length and inlet conditions of refrigerant to the capillary tube i.e. degree of subcooling, inlet pressure on the mass flow rate of the refrigerant, also investigation about the coiling effect of sp...

Liquid flowing through a thin-walled "collapsible" tube similar to a vein, inclined to any angle between vertical and slightly above horizontal, differs from the flow in rigid tubes in that: a "collapsible" tube accepts any flow presented to it without affecting the rate of flow through the system; the lateral pressure at all cross sections throughout the tube is zero and does not change as the...

The principle of heat transfer enhancement in the core flow of a tube has been proposed, in this paper, to make fluid temperature uniform in the core region of a tube and decrease flow resistance, which is different from heat transfer enhancement in the boundary flow of a tube. Two new models, representing heat transfer enhancement in the laminar and turbulent tube flow, have been established a...

We can classify the flow of a fluid in a straight circular tube into either laminar or turbulent flow. It is assumed from hereon that we assume fully developed incompressible, Newtonian, steady flow conditions. Fully developed flow implies that the tube is long compared with the entrance length in which the velocity distribution at the inlet adjusts itself to the geometry and no longer changes ...