Design of compact intermediate heat exchangers for gas cooled fast reactors

Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004. === Includes bibliographical references (p. 171-174). === Two aspects of an intermediate heat exchanger (IHX) for GFR service have been investigated: (1) the intrinsic characteristics of the proposed c...

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Main Author: Gezelius, Knut, 1978-
Other Authors: Michael J. Driscoll and Pavel Hejzlar.
Format: Others
Language:en_US
Published: Massachusetts Institute of Technology 2005
Subjects:
Online Access:http://hdl.handle.net/1721.1/26911
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spelling ndltd-MIT-oai-dspace.mit.edu-1721.1-269112019-05-02T16:38:17Z Design of compact intermediate heat exchangers for gas cooled fast reactors Gezelius, Knut, 1978- Michael J. Driscoll and Pavel Hejzlar. Massachusetts Institute of Technology. Dept. of Nuclear Engineering. Massachusetts Institute of Technology. Dept. of Nuclear Engineering. Nuclear Engineering. Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004. Includes bibliographical references (p. 171-174). Two aspects of an intermediate heat exchanger (IHX) for GFR service have been investigated: (1) the intrinsic characteristics of the proposed compact printed circuit heat exchanger (PCHE); and (2) a specific design optimizing economic and technical efficiency while coupling a supercritical CO2 Brayton power cycle to a helium cooled fast reactor core. In particular, the wavy channel friction factor and the effective conduction thickness between channels were evaluated by simulations using state of the art software (FluentTm). To support the competitiveness of the PCHE, it was directly compared to other potential IHX candidates with respect to performance and size for identical operating conditions. All PCHE modeling conservatively assumed straight channels and was carried out using an MIT in-house code. The PCHEs designed specifically for the He/S-CO2 cycle were designed to be deployed in a prestressed cast iron reactor vessel (PCIV) pod and to permit a net cycle efficiency of at least 40%. Optimization theory, sensitivity studies, and thermal-hydraulic constraints contributed to shaping the final design. The friction factor analysis showed that the correlations cited in the literature overestimate the value by approximately a factor of two. As regards the effective conduction thickness ratio, it was found to be around 0.6 for a 2.0 mm channel diameter. Since the value of the ratio employed in the MIT in-house code is 1.0, the results generated by the code should be conservative. Comparing the competing IHX types clearly illustrated the advantages of using a compact design, thus favoring PCHEs and plate-fin designs. A maximum net cycle efficiency of 40.9% was achieved for the proposed cycle utilizing a low-pressure-drop reference core. The cost and core volume of this 600 MWt PCHE design were estimated to be $2.4M and 16.4 inm3, respectively. The largest uncertainty associated with the computations is whether the PCIV pod provides sufficient space for deployment of the PCHE, a blower, and other ancillary equipment. However, studies of PCHEs based on zig-zag channels indicate that the compactness can be further enhanced by a factor of 2 to 3 thanks to the increased heat transfer capability of the saw-tooth channel geometry. More research is needed to verify this projection. by Knut Gezelius. S.M.and S.B. 2005-09-06T20:47:05Z 2005-09-06T20:47:05Z 2004 2004 Thesis http://hdl.handle.net/1721.1/26911 56504354 en_US M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 206 p. 7363907 bytes 7363714 bytes application/pdf application/pdf application/pdf Massachusetts Institute of Technology
collection NDLTD
language en_US
format Others
sources NDLTD
topic Nuclear Engineering.
spellingShingle Nuclear Engineering.
Gezelius, Knut, 1978-
Design of compact intermediate heat exchangers for gas cooled fast reactors
description Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004. === Includes bibliographical references (p. 171-174). === Two aspects of an intermediate heat exchanger (IHX) for GFR service have been investigated: (1) the intrinsic characteristics of the proposed compact printed circuit heat exchanger (PCHE); and (2) a specific design optimizing economic and technical efficiency while coupling a supercritical CO2 Brayton power cycle to a helium cooled fast reactor core. In particular, the wavy channel friction factor and the effective conduction thickness between channels were evaluated by simulations using state of the art software (FluentTm). To support the competitiveness of the PCHE, it was directly compared to other potential IHX candidates with respect to performance and size for identical operating conditions. All PCHE modeling conservatively assumed straight channels and was carried out using an MIT in-house code. The PCHEs designed specifically for the He/S-CO2 cycle were designed to be deployed in a prestressed cast iron reactor vessel (PCIV) pod and to permit a net cycle efficiency of at least 40%. Optimization theory, sensitivity studies, and thermal-hydraulic constraints contributed to shaping the final design. The friction factor analysis showed that the correlations cited in the literature overestimate the value by approximately a factor of two. As regards the effective conduction thickness ratio, it was found to be around 0.6 for a 2.0 mm channel diameter. Since the value of the ratio employed in the MIT in-house code is 1.0, the results generated by the code should be conservative. === Comparing the competing IHX types clearly illustrated the advantages of using a compact design, thus favoring PCHEs and plate-fin designs. A maximum net cycle efficiency of 40.9% was achieved for the proposed cycle utilizing a low-pressure-drop reference core. The cost and core volume of this 600 MWt PCHE design were estimated to be $2.4M and 16.4 inm3, respectively. The largest uncertainty associated with the computations is whether the PCIV pod provides sufficient space for deployment of the PCHE, a blower, and other ancillary equipment. However, studies of PCHEs based on zig-zag channels indicate that the compactness can be further enhanced by a factor of 2 to 3 thanks to the increased heat transfer capability of the saw-tooth channel geometry. More research is needed to verify this projection. === by Knut Gezelius. === S.M.and S.B.
author2 Michael J. Driscoll and Pavel Hejzlar.
author_facet Michael J. Driscoll and Pavel Hejzlar.
Gezelius, Knut, 1978-
author Gezelius, Knut, 1978-
author_sort Gezelius, Knut, 1978-
title Design of compact intermediate heat exchangers for gas cooled fast reactors
title_short Design of compact intermediate heat exchangers for gas cooled fast reactors
title_full Design of compact intermediate heat exchangers for gas cooled fast reactors
title_fullStr Design of compact intermediate heat exchangers for gas cooled fast reactors
title_full_unstemmed Design of compact intermediate heat exchangers for gas cooled fast reactors
title_sort design of compact intermediate heat exchangers for gas cooled fast reactors
publisher Massachusetts Institute of Technology
publishDate 2005
url http://hdl.handle.net/1721.1/26911
work_keys_str_mv AT gezeliusknut1978 designofcompactintermediateheatexchangersforgascooledfastreactors
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