Design of a Tesla Turbine: Transcritical CO2 Two-Phase Flow Analysis

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F24%3A00376418" target="_blank" >RIV/68407700:21220/24:00376418 - isvavai.cz</a>

Result on the web

<a href="https://www.esat2024.eng.ed.ac.uk/sites/esat2024.eng.ed.ac.uk/files/ESAT_2024_Book_of_Abstracts.pdf" target="_blank" >https://www.esat2024.eng.ed.ac.uk/sites/esat2024.eng.ed.ac.uk/files/ESAT_2024_Book_of_Abstracts.pdf</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Design of a Tesla Turbine: Transcritical CO2 Two-Phase Flow Analysis

Original language description

The efficiency of CO2 heat pumps is optimal only under transcritical conditions, which poses challenges in isenthalpic expansion and subsequent energy waste. This study explores the potential of recovering energy through isenthalpic expansion, which transitions the fluid from supercritical to subcritical state. The Tesla turbine emerges as a solution for energy recovery, but its application introduces complexities, especially in handling two-phase flow. Attention is directed towards designing critical parameters, crucial from a fluid mechanics perspective. Constraints, such as limited fluid availability and considerations for pipeline design pressure, further shape the experimental setup. This research focusses on estimating the critical speed and pressure in two-phase CO2 flow for Tesla turbine design. It proposes a method that combines elements from Andrianova et al. (1981) while extending the range of critical pressure analysis, bypassing the need for an ideal-gas approach. The method relies on an energy conservation analysis of local flow speed through enthalpy variation ???????????? = root 2(ℎ0 - ℎ????????), contrasted with the definition of speed of sound ????* = root - (????????/????????)|????/(????)^2 . A comparative analysis with the ideal gas approach enhances understanding. The stagnation properties, derived from CoolProp, including temperature, pressure, enthalpy, and other thermodynamic properties, form the basis for the design points. The methodology employs a comprehensive representation of the results, incorporating isobars, isotherms, and intersection points between the local flow speed and the sound speed. Computational efficiency is ensured through interval divisions and careful consideration of invalid intersections, while three-dimensional plots depict critical speeds and speed times density. In conclusion, this research contributes valuable information on the critical dynamics of two-phase CO2 flow in Tesla turbine applications, providing a foundation for optimising energy recovery processes and designing more efficient CO2 heat pump systems.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20303 - Thermodynamics

Project

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Continuities

S - Specificky vyzkum na vysokych skolach

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů