Doctoral Dissertations

Keywords and Phrases

Dryout; Post-CHF

Abstract

"Understanding heat transfer in the post-critical heat flux (CHF) flow boiling regime is important for determining the performance of the heat transfer equipment for various industrial applications requiring high heat transfer rates, e.g., heat exchangers, boilers, chemical and nuclear reactors. Liquid can be present in the core of the flow channel in the form of entrained liquid droplets, especially immediately downstream of film dryout. These droplets are suspected to provide an important heat transfer mechanism as they impinge on the heated wall. The objective of the current study is to investigate liquid contact with the heated wall in this flow region immediately downstream of the film dryout location. As part of this study a thermal hydraulic test loop (Experimental Vertrel Loop) was designed and constructed to conduct flow boiling experiments using Vertrel XF as the heat transfer fluid. A test section, with a rectangular flow geometry to enable a simplified 2D flow field and optical access for flow visualization, was designed and fabricated to study CHF and developing post-dryout flow boiling. Heater surface mounted thermistors were developed to facilitate wall temperature measurement and liquid contact detection. CHF and liquid contact data was collected for twenty different test conditions with exit pressures ranging from 221 to 287KPa, inlet temperatures ranging from 318 to 339K and mass fluxes ranging from 1025 to 2050kg/m2s. A data set consisting of over 500 liquid contact fraction data points was generated for steady-state developing post-dryout flow boiling regime. A correlation has been developed based on the test data to predict the liquid contact fraction and enable heat transfer prediction of the transition from CHF to fully developed post-dryout flow. The proposed correlation predicts 97% of the liquid contact fraction test data with an average error of 9:7% and a root mean square error of 11:9%"--Abstract, page iii.

Advisor(s)

Mueller, Gary Edward, 1954-

Committee Member(s)

Schlegel, Joshua P.
Castano Giraldo, Carlos Henry
Lee, Hyoung-Koo
Strayer, T. Darton

Department(s)

Mining and Nuclear Engineering

Degree Name

Ph. D. in Nuclear Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2019

Pagination

xx, 221 pages

Note about bibliography

Includes bibliographic references (pages 215-220).

Rights

© 2019 Hirallkumar Harshadbhai Patel, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11548

Electronic OCLC #

1105154972

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