Design and Optimization of Compact Printed Circuit Heat Exchanger as s-CO2 Brayton Cycle Regenerator by Using Sub-Heat Exchanger Model


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ARSLAN F. , GÜZEL B.

IV INTERNATIONAL CONFERENCE ON ENGINEERING AND NATURAL SCIENCES (ICENS), Kiev, Ukraine, 2 - 06 May 2018, pp.398

  • Publication Type: Conference Paper / Summary Text
  • City: Kiev
  • Country: Ukraine
  • Page Numbers: pp.398

Abstract

The super-critical carbon-dioxide (s-CO2) regenerative Brayton power cycle comes to forefront with its high thermal efficiency and high power density. The s-CO2 Brayton cycle achieves compact turbo-machine dimensions thanks to its high power density advantage. In addition, compact heat exchangers are also needed to build compact power systems. In this study, compact printed circuit heat exchanger (PCHE) as Brayton cycle regenerator was designed by using sub-heat exchanger model. Sub-heat exchanger model gives better results when compared bulk temperature approach because of fluxional thermo-physical properties of s-CO2. Heat exchanger structural design is made according to American Society of Mechanical Engineers (ASME) standards. Thermal performance analyzes were performed using both logarithmic mean temperature difference (LMTD) and number of transfer units (NTU)-effectiveness methods. Different Nusselt and different friction factor correlations are used in the thermal-hydraulic performance analyzes and the results are presented in comparison. The effects of different channel diameters on heat exchanger size and weight have been examined. PCHEs are seen to be advantageous in terms of size and weight thanks to their compact structure.

Keywords: Super-critical carbon-dioxide, Printed circuit heat exchanger, Sub-heat exchanger model