Abstract
Abstract Non-Ideal Compressible Fluid-Dynamics (NICFD) has recently been established as a sector of fluid mechanics dealing with the flows of dense vapors, supercritical fluids, and two-phase fluids, whose properties significantly depart from those of the ideal gas. The flow through an Organic Rankine Cycle (ORC) turbine is an exemplary application, as stators often operate in the supersonic and transonic regime, and are affected by NICFD effects. Other applications are turbomachinery using supercritical CO2 as working fluid or other fluids typical of the oil and gas industry, and components of air conditioning and refrigeration systems. Due to the comparably lower level of experience in the design of this fluid machinery, and the lack of experimental information on NICFD flows, the design of the main components of these processes (i.e., turbomachinery and nozzles) may benefit from adjoint-based automated fluid-dynamic shape optimization. Hence, this work is related to the development and testing of a fully-turbulent adjoint method capable of treating NICFD flows. The method was implemented within the SU2 open-source software infrastructure. The adjoint solver was obtained by linearizing the discretized flow equations and the fluid thermodynamic models by means of advanced Automatic Differentiation (AD) techniques. The new adjoint solver was tested on exemplary turbomachinery cases. Results demonstrate the method effectiveness in improving simulated fluid-dynamic performance, and underline the importance of accurately modeling non-ideal thermodynamic and viscous effects when optimizing internal flows influenced by NICFD phenomena.
Highlights
Non-Ideal Compressible Fluid-Dynamics (NICFD) is a new branch of fluid-mechanics (NICFD, 2016) concerned with the flows of dense vapors, supercritical fluids, and two-phase fluids, in cases in which the ideal gas law does not apply.In these flows, the isentropic variation of the speed of sound with density is different if compared to the flow of an idealVitale et al | Design method for turbomachinery working in the NICFD regime https://journal.gpps.global/a/Z1FVOI/gas (Cramer, 1991); the flow field is bound to be quantitatively (Harinck et al, 2009) or even qualitatively different (Zamfirescu et al, 2008).NICFD internal flows occur in numerous heterogeneous industrial processes
The results demonstrate the importance of accurately modeling non-ideal thermodynamic and viscous effects for adjoint-based Fluid-dynamic shape optimization (FSO) applied to NICFD applications
The capabilities of the FSO method described in the previous section were demonstrated by redesigning a supersonic and a transonic cascade that are representative of typical cascades adopted in single-stage and multi-stage Organic Rankine Cycle (ORC) turbines (Colonna et al, 2015)
Summary
NICFD is a new branch of fluid-mechanics (NICFD, 2016) concerned with the flows of dense vapors, supercritical fluids, and two-phase fluids, in cases in which the ideal gas law does not apply.In these flows, the isentropic variation of the speed of sound with density is different if compared to the flow of an idealVitale et al | Design method for turbomachinery working in the NICFD regime https://journal.gpps.global/a/Z1FVOI/gas (Cramer, 1991); the flow field is bound to be quantitatively (Harinck et al, 2009) or even qualitatively different (Zamfirescu et al, 2008).NICFD internal flows occur in numerous heterogeneous industrial processes. The results demonstrate the importance of accurately modeling non-ideal thermodynamic and viscous effects for adjoint-based FSO applied to NICFD applications.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the Global Power and Propulsion Society
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
