Date of Award:

2012

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Mechanical and Aerospace Engineering

Advisor/Chair:

Heng Ban

Abstract

The Boosted Fast Flux Loop (BFFL) will expand the Advanced Test Reactor (ATR) at Idaho National Laboratory. Part of the BFFL is a new corrosion test cap section for testing in the ATR. The corrosion test cap section was designed with parallel channels to reduce the pressure drop and allow coolant contact with specimens. The fluid experiment conducted by Idaho State University found the pressure drop not characteristic of parallel channel flow but greater than without parallel channels. A Computation Fluid Dynamics simulation using STAR-CCM+ was conducted with the objectives of showing sufficient flow through the test cap section for a corrosion test, verifying the fluid experiment's validity, and explaining the abnormal pressure drop. The simulation used a polyhedral volume mesh and the k-e turbulent model with segregated equations. Convergence depended on a low continuity residual and an unchanging pressure drop result. The simulation showed the same pattern as the fluid experiment. The simulation provided evidence of flow through the test cap section needed for a corrosion test. The specimen holding assembly was found to be a small contributor to the pressure drop. The counterintuitive pressure drop was found to be the sum of many factors produced from the geometry of the test cap section. The inlet of the test cap section behaved as a diverging nozzle before a sudden expansion into the test cap section chamber with both creating a pressure drop. The chaotic flow inside the chamber gave rise to pressure loss from mixing. The fluid exited the chamber through a sudden contraction to a converging nozzle behaving exit, again, producing a pressure drop. By varying the flow rate in the simulation, a disturbance in the flow where the gap fluid separated into the parallel channels was found at high flow rates. At low flow rates the pressure drop anomaly was not found. The corrosion test cap section could be used in the ATR but with a higher pressure drop than desirable. The design of the corrosion test cap section created the abnormal pressure drop.

Comments

This work made publicly available electronically on December 21, 2012.

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