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Abstract:There is a strong tendency for two immiscible fluids to arrange themselves so that the low viscosity constituent is in the region of high share. Therefore, it may be possible to introduce a beneficial effect in any flow of a very viscous liquid by introducing amount of a fluid lubricated as liquid-liquid oil-water flow. Two main classes of flows are seen, annular and small bubble in all experimental results. The pressure drop and mean heat-transfer coefficients were observed to depend strongly on the flow patterns. A correlation of the two-phase mean heat-transfer coefficients, based on a simple model of liquid flow, with a Reynolds number based on the actual mean velocity of the liquid mixture two-phase flow, were developed. An experimental rig facility has been designed and constructed, to enable measurements of local parameters in oil-water flow in the developing region of the flow in a 32 mm ID 6 m long pipe. The large discrepancies between model predictions and experimental data are reported in the literature review that the physics of oil-water flow is complex and not yet fully understood. The flow patterns that appear are classified in flow pattern maps as functions of either mixture velocity and water cut or superficial velocities. From these experiments a smaller number of annular flows are selected for studies of velocity and turbulence. The theoretical study was executed using software Fluent program, a modified turbulent diffusion model is presented. Simulation results carried out with the model show more physical predictions with respect to the particle deposition process and concentration profile. The theoretical results represent the pressure gradient distribution, velocity and mean heat transfer coefficient, pressure contours, velocity vectors, streamlines, and also velocity profiles. It was found that the methods with more restrictions (in terms of the applicable range of void fraction, liquid superficial Reynolds number) give better predictions.

This study presents an experimental investigation of metastable region take place forrefrigerant flow through adiabatic and non-adiabatic capillary tube of window type airconditioner. Large numbers of experiments are carried out to explain the effect of length ofstraight and helical capillary tube on metastable region under adiabatic and non-adiabaticconditions. for the case of adiabatic capillary tube, three different length are selected(70,100 and 150) cm and two helical capillary tube, the length of each tube is 100 cm withtwo coil diameters (2 and 6) cm. For the non-adiabatic capillary tube, the straight capillarytube suction line is 150 cm while the length of non-adiabatic helical capillary tube is 200 cmwith 8 cm coil diameter. The results show that the length is the most influence parameterson beginning of metastable region. In addition the helical coil tube effect on the beginningof metastable region. As well as for the adiabatic and non-adiabatic capillary tube it isconcluded that mass flow rate is the main parameters on beginning of metastable region.Also effect of length and coiling on both pressure drop and mass flow rate are discussed.The CFD commercial code, ANSYS CFX 16.1 based on finite volume method using Kturbulencemodel considering the homogeneous flow between phases applied to straightcapillary tube. The present numerical data has been validated with the present workexperimental data and with other researchers. A good agreement is obtained which can belead to use ANSYS CFX 16.1 in the design and optimization of capillary tube in airconditioner.

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