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Experimental investigations on control of flow instability in single-phase natural circulation loop

  • K. Bodkha , N. Kumar and P. K. Vijayan
Published/Copyright: September 9, 2013
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Abstract

Natural circulation systems offer simplicity, enhanced safety and reliability and thus are advantageous over their forced circulation counterpart. However, natural circulation is susceptible to flow instabilities. These instabilities are undesirable for various reasons. Literature suggests the use of orifices at the inlet to suppress instability. However, orificing introduces pressure drop which limits the flow rate and hence the heat carrying capacity of the fluid. In the present study, investigations have been carried out with different mechanical gadgets to control the natural circulation flow instabilities. Extensive experiments have been carried out in a single-phase rectangular natural circulation loop to study the effect of these mechanical gadgets on instability. The paper brings out the results of experimental investigations carried out on the role of mechanical gadgets in controlling instability.

Kurzfassung

Naturumlaufsysteme bieten Einfachheit, erhöhte Sicherheit und Zuverlässigkeit und sind deshalb von Vorteil gegenüber Systemen mit erzwungenem Umlauf. Der Naturumlauf ist jedoch anfällig gegenüber Strömungsinstabilitäten. Solche Instabilitäten sind aus verschiedenen Gründen unerwünscht. In der Literatur wird die Verwendung von Öffnungen am Einlass zur Unterdrückung von Instabilitäten beschrieben. Öffnungen bewirken jedoch einen Druckabfall, der die Strömungsgeschwindigkeit begrenzt und damit die Wärmeleitfähigkeit. In dem vorliegenden Arbeit wurden Untersuchungen durchgeführt mit verschiedenen mechanischen Vorrichtungen zur Kontrolle der Strömungsinstabilitäten beim Naturumlauf. Umfangreiche Experimente wurden in einem einphasigen rechteckigen Naturumlaufsystem durchgeführt, um die Wirkung dieser mechanischen Vorrichtungen auf die Instabilitäten zu untersuchen. Der Beitrag präsentiert die Ergebnisse experimenteller Untersuchungen mit mechanischen Vorrichtungen zur Kontrolle von Instabilitäten.

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Received: 2012-9-7
Published Online: 2013-09-09
Published in Print: 2013-06-28

© 2013, Carl Hanser Verlag, München

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