Session: 37-02 Radial Turbomachinery Design

Paper Number: 151238

Cryogenic Radial Turbine Design for High-Efficiency Hydrogen Liquefaction Plants 

Meeting the rising liquefied hydrogen demand will require a scale-up of liquefaction infrastructure. Higher plant capacities increase the viability of novel cycles and components that can achieve improved yield and efficiency.

This paper describes a high-efficiency configuration that utilises a turboexpander in the final hydrogen expansion. Conventionally, this final expansion is performed isenthalpically in a single Joule-Thompson valve (baseline). In the novel configuration, the expansion is split into two parts. The first part of the expansion is performed in a single-phase turboexpander; then, the remaining pressure drop is achieved using a two-phase expansion in a Joule-Thomson valve. The study shows that the novel configuration increases yield by 13.3 percentage points and exergetic efficiency by 4.6 percentage points for the cycle analysed, compared to the baseline.

A proof-of-concept for radial turbine design for this application is developed. The turbine inlet condition is hydrogen at 50 bar and 30.7 K. The outlet pressure is 16.7 bar, corresponding to a pressure ratio of 3. The turbine is assumed to have a mass flow rate of 2 kg/s corresponding to a plant capacity of 100 tpd.

The aerodynamic design is performed on a modified version of the open-source turbomachinery design code TURBIGEN. From a radial-turbine meanline code and geometry parameters, the annulus and blade geometry are obtained and subsequently run on a RANS solver with real gas property tables from Coolprop. This coupled process enables rapid investigation of the design space. The effects of tip gap, capacity, inlet angle and off-design conditions on performance are analysed. The optimised aerodynamic datum design is then assessed for mechanical and manufacturability constraints. The final design is then evaluated, and the resulting performance included in the cycle model, confirming the target increased yield and exergetic efficiency of the liquefaction cycle.

Presenting Author: Alicia Torres Gomez University of Cambridge

Presenting Author Biography: Alicia Torres Gomez is a PhD candidate at the Whittle Laboratory, University of Cambridge, as part of the Centre for Doctoral Training in Future Propulsion and Power. She completed her undergraduate degree with integrated master's in Aeronautical and Mechanical Engineering at the University of Cambridge in 2020 and was awarded the Amelia Earhart Fellowship in 2023.

Authors:

Alicia Torres Gomez University of Cambridge
James Brind University of Cambridge
Graham Pullan University of Cambridge