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Session: Session 9: Heat exchangers
Session starts: Tuesday 13 October, 08:40
Presentation starts: 09:40
Room: 1B Europe

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Parsa Mirmobin ()
Chris Sellers ()

Abstract:
Organic Rankine Cycles are typically utilized where steady heat source and condensing conditions prevail. In highly transient cases, the working fluid often undergoes violent phase transition within the evaporator. The resulting forces are experienced by the heat exchanger, expander, and associated piping. This ultimately results in premature and catastrophic component failure. This paper discusses pressure and flow instability which occurs during initial startup of an ORC. The instability is a result of a nonlinear pressure field within the evaporator interacting with the pressure source (centrifugal pump.) The phenomenon is characterized by a rapid oscillation in pressure and flow and resembles similar effects observed in low pressure boilers; the so called Ledinegg instability. Experimental data is examined and various methods for reducing or eliminating this effect are presented.