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Abstract

The problem of condensing annular flow inside a horizontal tube was studied experimentally and theoretically.

In the experimental investigation measurements of the local heat transfer coefficient and pressure drop were made for condensing steam inside a 38.1 mm I.D. and 3.0 m long horizontal tube.

The range of conditions covered during the experimental study was:

1. Condensing pressure, 0.4 - 0.6 Bar (abs)
2. Inlet superheat, O - 1.0°C
3. Coolant flow rate, 5342 - 9687 kg/hr
4. Inlet quality, 0.55 - 1.0
5. Exit quality, 0.30 - 0.68
6. Vapour mass velocity, 134200 - 620497 kg/hr-m2
7. Inlet velocity, 97 - 186 m/s

A wall suction device was used to measure the liquid film flow rate at the end of the test section. The liquid entrainment at this point was evaluated from these measurements.

The experimental entrainment results were plotted on a basis of existing correlating parameters for adiabatic two-phase flow and the data points were reasonably well represented by a single curve.

The local heat transfer coefficient was found to increase and decrease along the condenser tube. A correlation equation is presented for the pressure drop based on the Martinelli pressure parameters.

The theoretical analysis was based on the assumption that during condensation, the flow pattern was annular. The flow was divided into a droplets-vapour core and an axisymmetric liquid film. The resulting set of six non-linear partial differential equations were solved numerically with the use of a digital computer. Good agreement was found between the theoretical and experimental values of pressure drop, vapour quality and liquid film flow rate.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General) T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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