Transforming heat-recovery system performance by exploiting multi component turbine flows

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

Living standards in the UK are at significant risk from the rising costs of energy and the increasing gap between demand and the UK's generating capacity. Plugging this gap requires technological innovations which are affordable and can be implemented over reasonably short time-scales. An important area where efficiency gains can be achieved quickly is improving the management of heat released from industrial processes. All industrial and power generation processes produce heat which is often released into the environment in the form of high temperature exhaust products. New technologies are being developed to recover this otherwise wasted energy for use elsewhere, such as electricity, heating or cooling. If applied across the UK manufacturing sector, these technologies could save the energy output of around 20 power stations. Heat-recovery technologies are also used for renewable power from biomass, geothermal, solar-thermal sources and in de-centralized power generation. The development of heat recovery technology is therefore important in terms of cutting our carbon footprint as well as increasing UK energy security.

Heat recovery systems work by transferring heat into a high-pressure working-fluid, using a heat exchanger. In order to produce electricity, the working fluid drives a turbine which is connected to an electrical generator. Heat recovery systems often use working fluids which are refrigerants or long-chain hydrocarbons. The properties of these working fluids differ greatly from those which have traditionally been used within turbines (such as air within aero-engines/gas-turbines or water vapour within steam turbines) and can be made up of several components including mixtures of gases and liquids. There is very little known about the behaviour of these unconventional working fluids within turbines largely due to a lack of experimental data with which to test current theories. This is important because turbine designers require accurate models in order to develop high performance machines, and uncertainties in the modelling can have a detrimental impact on both the development costs and the overall performance of a heat recovery system. There is also a potential to exploit the unusual behaviour of these working fluids, such as their ability to change from liquid to gas across the turbine, which can be exploited to increase system power to size ratios (power density) in ways not possible using normal working fluids like water.

The project will explore how the behaviour of multi-component fluids can be used to increase turbine performance. In order to achieve this, the work will involve developing methods to simulate multi-component fluids within turbines. The project will use experiments and computational techniques to model these flows and use the results from this work to improve current computational methods. The project involves a collaboration with GE who are global leader in the design, manufacture and supply of heat recovery systems. GE will incorporate the results of this work into their design systems. In doing so, the results from this project will accelerate the development of heat-recovery technologies which will be used world-wide.

Planned Impact

Heat recovery systems are used in a wide range of low carbon technologies such as co-generation, biomass, solar, geothermal. Heat recovery systems can also be used to reduce energy demand in industrial processes; it is estimated that around 40TWh of energy can be recovered from UK industries through the implementation of heat recovery technologies. Given that the global market for low carbon technologies is estimated to increase to nearly £900bn by 2050, growth in research capabilities in these technologies is very important for maintaining UK competitiveness in the future.

The economic and societal benefits of developments in heat recovery technologies are large due to the rising pressures for increased sustainability of energy supply. According to Ofgem, spare electricity power production capacity could fall to 2% by 2015, which means that measures to reduce energy demand are urgently needed and technological solutions must be delivered rapidly. The implementation of heat recovery systems can help to alleviate these risks by improving how we manage heat released from many industries. This can have a transformative impact on UK energy use, particularly in the manufacturing industries which will be required to reduce emissions by up to 70% to meet the UK 2050 targets.

This project will help put the UK at the forefront of this emerging field and attract research investment from market leaders, such as GE, who are committed to providing financial support for this project. GE's support for this project provides a route to exploitation of this work and will ensure the results impact technological developments in the near term. This means that the results from the project will have a significant global impact as GE provide heat recovery systems internationally for a large number of applications including reciprocating engines, biomass boilers and micro-turbines, and industries including waste-treatment, oil and gas and agriculture. The results from the work will be published in a broad range of academic and public media, and will therefore be available to beneficiaries working in industry and academia. The dissemination of this work will be further facilitated through a number of events, such as workshops and public road-shows, and using several social and on-line media.

The importance of this work stems from its potential to increase UK competitiveness and energy sustainability and is further strengthened by its cross-disciplinary relevance to an extensive range of technologies and research areas. The focus of this work on transonic/highly-loaded turbines means that the results will have impact to many turbine applications where power-to-weight or specific cost is critical. As well as this, the focus of the work on multi-phase effects provides a strong link with oil and gas pumping and steam-turbines which also suffer from two-phase flows; these technologies are vital to current power generation. The study of multi-component fluids is also integral to understanding many chemical and biological processes, and so this project has the potential to lead to technological developments in several other turbomachinery applications and engineering disciplines.

Publications

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Baumgärtner D (2020) The Effect of Isentropic Exponent on Transonic Turbine Performance in Journal of Turbomachinery

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Durá Galiana F (2016) A Study of Trailing-Edge Losses in Organic Rankine Cycle Turbines in Journal of Turbomachinery

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Durá Galiana F (2017) The effect of dense gas dynamics on loss in ORC transonic turbines in Journal of Physics: Conference Series

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Galiana, Francisco J. Dura (2015) A STUDY OF TRAILING-EDGE LOSSES IN ORGANIC RANKINE CYCLE TURBINES in Asme Turbo Expo: Turbine Technical Conference and Exposition, 2015, Vol 2a

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Wheeler A (2018) The Effect of Nonequilibrium Boundary Layers on Compressor Performance in Journal of Turbomachinery

 
Description Our experimental and computational work to-date reveal the behaviour of complex gas flows in turbines used for waste heat recovery. The so-called 'dense gases' behave very differently from gases used in conventional turbines (such as gas turbines and steam turbines), and can be exploited for recovering low-grade heat. Our results show that the performance of the turbine is greatly modified by 'dense-gas' effects, leading to large differences in the flow structure and loss mechanisms. We have developed a unique experimental test facility for testing independently working-fluid and turbine design. We have also used experimental data to validate current computational methods for simulating these flows, as well as developing our own reduced-order models to predict the infuence of these effects on turbine performance. These methods can be included within the turbine design process.
Our recent results show that the working fluid properties plays a critical role in turbine loss. We find that a key parameter affecting loss is the isentropic exponent, which varies significantly between different working fluids, and also for gases at high pressure levels and temperatures. Our results show that this parameter can alter turbine loss by between 20%-35%, depending on turbine design. The results are important for future turbines used for low-Carbon power and and/or those where high gas temperatures and pressures can exist (such as in aero-engine high pressure turbines).
Exploitation Route The results are important for future turbines used for low-Carbon power and and/or those where high gas temperatures and pressures can exist (such as in aero-engine high pressure turbines). We have been able to derive a low-order model for the effects of isentropic exponent on turbine performance which can be used for future turbine designs.
Sectors Aerospace, Defence and Marine,Energy

URL https://whittle.eng.cam.ac.uk/research-areas/transonic-turbines-for-low-carbon-power-cycles/
 
Description Denton Studentship
Amount £56,000 (GBP)
Organisation University of Cambridge 
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 10/2019
 
Description EPSRC DTP Studentship
Amount £24,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 10/2016 
End 10/2019
 
Description EPSRC Tier-2 Resource Allocation
Amount £40,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 07/2018 
End 06/2019
 
Description EPSRC Tier-2 Resource Allocation
Amount £40,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 10/2018 
End 10/2019
 
Title Method of simulating Organic Rankine Cycle turbine flows 
Description We have developed a new transient wind tunnel which simulates the flows found in Organic Rankine Cycle turbines. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact We have recently published results from this facility showing how the flow behaviour in an Organic Rankine Cycle turbine is greatly dependent on the choice of working fluid. 
URL http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2427865
 
Title ORC Supersonic Cascade Facility 
Description We have recently developed a new experimental method for simulating supersonic flows within Organic Rankine Cycle turbines. The facility is based on a transient Ludwieg tube wind tunnel with a novel working section with modular turbine-vane test models. We make use of new rapid manufacturing methods, where we are able to generate turbine vane blisks (bladed-disks) in-house and test them within the facility. The facility is unique for its capability to change working-fluid and vane geometry independently. 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact At present we are still collecting data from this facility. 
URL https://whittle.eng.cam.ac.uk/research-areas/transonic-turbines-for-low-carbon-power-cycles/
 
Title Real-Gas Navier-Stokes Solver 
Description A new high-order Navier-Stokes solver for the solution of turbomachinery flows including real-gas effects. The solver is a 4th order three-dimensional compressible scheme. 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? Yes  
Impact We are currently using this tool to study turbulent flows within turbomachinery, and for ORC turbines we are studying transonic trailing-edge flows. 
URL https://whittle.eng.cam.ac.uk/lab/team/andrew-wheeler/
 
Description Industrial Collaboration with Rolls Royce 
Organisation Rolls Royce Group Plc
Country United Kingdom 
Sector Private 
PI Contribution We are applying our research of multi-component and molecularly complex fluids, to a thermal management system design project. The details are commercially sensitive at this stage
Collaborator Contribution This is commercially sensitive at this stage
Impact This is commercially sensitive at this stage
Start Year 2019
 
Description Industrial collaboration with GE Global Research 
Organisation General Electric
Department GE Global Research
Country India 
Sector Private 
PI Contribution GE are a global leader in turbomachinery, and in waste heat recovery systems such as ORC turbines. We are working closely with GE who will make use of the results of our work within theire design systems
Collaborator Contribution GE are profividing valuable guidance on turbine design which aids us in the development of our experimental and computational simulations to ensure they represent correctly the true turbine environment. They are providing financial support and in-kind support for my EPSRC Fellowship and also supported my earlier EPSRC First Grant Proposal.
Impact The collaboration as led to the following publications: https://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleID=1735630 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2427865 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1907813&resultClick=1
Start Year 2010
 
Title 3DNS-RGAS 
Description A new 4th order accurate Navier-Stokes solver for the solution of real-gas flows in turbomachinery. The code solves the compressible Navier-Stokes equations including equations of state for real-gases such as Pentane for studying ORC turbine flows. The code is designed for high-fidelity scale-resolving simulations to capture the turbulent flow within turbomachines. 
Type Of Technology Software 
Year Produced 2017 
Impact The code is a development of the 3DNS code, which is being used to study turbomachinery flows of ideal-gases in compressors and the effect of non-equilibrium turbulence on compressor performance. This led to a recent publication presented at the ASME Turbo Expo 2017. 
URL http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2649652
 
Description Co-organizer of the first NICFD 2016 Conference 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact The aim of this event was to gather together a new international cross-disciplenary community of people that are interested in discussing the fluid dynamics of non-ideal compressible flows (NICFD). The growing interest towards NICFD in the last decade, especially for its advanced applications in the field of propulsion and power, has determined an impulse in research. This conference is intended to promote the exchange of information among the quite diverse community, whose interests span from the fundamentals to the industrial application.
Year(s) Of Engagement Activity 2016
URL http://www.kcorc.org/en/news-and-events/nicfd-2016-1st-international-seminar-non-ideal-com/
 
Description Organizer of the Whittle Laboratory Science Festival Event 2016 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I organized the first Whittle Laboratory Open Day as part of Cambridge Science Festival. We open our doors to the general public, who were able to participate in many demonstrations, table-top experiments, lab tours and computer simulations of work we are engaged in related to turbomachinery, low-carbon power, and propulsion. Over 600 people attended, with ages ranging form 0-80 years. Many people commented on how much they enjoyed the activity and how educational it was.
Year(s) Of Engagement Activity 2016
URL https://whittle.eng.cam.ac.uk/updates/2016/apr/2/whittle-laboratory-science-festival/
 
Description Organizer of the Whittle Laboratory Science Festival Event 2017 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I organized this Whittle Laboratory Open Day as part of Cambridge Science Festival. We open our doors to the general public, who were able to participate in many demonstrations, table-top experiments, lab tours and computer simulations of work we are engaged in related to turbomachinery, low-carbon power, and propulsion. This year around 500 people attended, with ages ranging form 0-80 years. Many people commented on how much they enjoyed the activity and how educational it was.
Year(s) Of Engagement Activity 2017
URL https://whittle.eng.cam.ac.uk/updates/2017/mar/10/2017-whittle-lab-open-day/
 
Description The Cambridge workshop on Turbomachinery for heat recovery and low-carbon power 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This 1-day workshop, organized and run by Dr Andy Wheeler, brought together academics, research students and people working in industry, involved in turbomachinery and thermofluid dynamics of real-gas flows. The workshop discussed the technological and research challenges for modern and future low-carbon technologies, such as low-carbon power generation, advanced cycles and heat recovery systems.The topics for discussion were:
Organic Rankine Cycles
Supercritical CO2
Non-equilibrium flows
Thermodynamic Cycle analysis
Real-gas/Dense-gas flows
There were international speakers from industry leaders (GE, Alstom) and Universities from across Europe, and attendees from across the UK, Europe and the US. The meeting and discussions that followed have led to a new network of interested parties involved in the development of turbomachinery for low-carbon technologies.
Year(s) Of Engagement Activity 2015
URL http://heat-recovery.eng.cam.ac.uk/WebHome