Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

Yehuda Taitel
School of Mechanical Engineering, Tel-Aviv University, Israel

U. Minzer
Tel-Aviv University, Tel-Aviv, Israel

Dvora Barnea
School of Mechanical Engineering, Tel-Aviv University, Tel-Aviv, Israel

The motivation for the present work is related to the use of parabolic trough solar power technology for direct steam generation (DSG). So far, commercial plants use liquid oil to absorb heat from the collectors, and steam is produced in heat exchangers. A more efficient process of direct steam generation in the collectors is not used due to possible uneven flow rate distribution and other instabilities, related to liquid-vapor flow in parallel pipes.
In this work we present an analysis and experimental results for the flow distribution of water flowing and evaporating in two parallel pipes with common inlet and outlet manifolds.
A new simplified model that yields the pressure drop vs. the flow rate in a single pipe is developed. This model is the basis for the calculation of steady state solutions, stability analysis and transient simulations in two parallel pipes.
Multiple steady state solutions may be obtained depending on the flow rate and the heating power. Linear stability analysis and transient simulations allow to differentiate between stable and unstable steady states. Experimental results compare well with the theoretical solutions.

HEX-20 pages DOI: 10.1615/IHTC13.p18.200 Download article

Article price - $35.00

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