Lockdown to Recovery: Understanding Interactions and Effects of Products/Processes Performance Through Computational Research with ASTUTE 2020
Improving manufacturing processes and manufactured products often require experimentation. Along with a costly ‘trial and error’ approach, this can be a lengthy process with an uncertain outcome. Computational Modelling is an essential tool that can increase the understanding of complex processes and products. In this article, we look specifically at Computational Fluid Dynamics (CFD) and how it can support manufacturing business in understanding complex processes and products.
Computational Fluid Dynamics for Manufacturing – What Does This Mean and What Does It Entail?
Fluids are present in all manufacturing sectors, from automotive to energy to process to building, to name a few. Understanding the relationship between fluid flow and the performance of a manufacturing process is very important to improve the process design and potentially create a new, more efficient and sustainable process. To quantify the effect of fluid flow on manufacturing processes there is a versatile method that can model fluid flow with high fidelity and provide detailed information about how the fluid flow impacts manufacturing processes. This method is called ‘Computational Fluid Dynamics’.
CFD is a branch of fluid mechanics that uses numerical analysis, data structures and computers to solve the equations describing the flow of fluids. CFD is a tool with amazing flexibility, accuracy and breadth of application such as laminar and turbulent flows, incompressible and compressible fluids, multiphase flows, heat and mass transfer, and chemical reactions.
The diagram below shows the different stages of a CFD simulation. It starts with a CAD of the fluid domain in the process to be modelled. The next step is to mesh the fluid domain, i.e. breaking it down into cells or elements on which the flow and associated phenomena, such as heat transfer, are solved. With the mesh ready the next step is building the CFD model by selecting the appropriate process physics (such as heat transfer, multiphase flow, turbulence … etc.), assigning boundary conditions, defining operating conditions and selecting the simulations type (steady-state or transient). Before invoking the solver, the fluid domain is initialised, the convergence criterion is set and the number of cores that will do the number crunching is selected. Next step will be solving the CFD model’s equations. The last step will be post-processing the simulation results to extract the required information from the fluid domain and interpret them.
Stages of a CFD simulation
The post-processing outcome could be used to improve the process design by changing the geometry and repeating the subsequent steps of the fluid domain. This iterative process continues until a suitable design has been reached.
There are several CFD software packages available, they fall into two categories: commercial or open-source. The most widely used commercial package is ANSYS CFD and it contains two solvers: CFX and Fluent. CFX is a cell-vertex finite element solver and Fluent is a cell-centred finite volume solver. The most widely used open-source CFD package is OpenFOAM, a cell-centred finite volume solver. All these packages run under Windows and Linux operating systems. The ASTUTE 2020 CFD team has in-depth expertise in the above three packages gained from wide-ranging applications to real-life challenges.
How CFD Can Increase the Understanding of Issues and Challenges Within Complex Processes
CFD can increase understanding of complex processes by:
- Providing detailed information throughout the fluid domain. Such information could be very difficult, and therefore very expensive, or impossible to obtain in real-life processes due to complex geometries, device dimensions, challenging/harsh operating conditions, materials of construction.
- Allowing the user to do sensitivity analysis to explore which process variables have the greatest impact on the process performance and aid the user in planning mitigation measures should process performance deteriorates or the process becomes unsafe.
- Allowing the user to do ‘what-if’ scenarios to determine if a process will fail. Such information is very helpful in determining if the process is safe or not.
How Can ASTUTE 2020 Expertise in CFD Benefit the Welsh Manufacturing Industry?
CFD can benefit the Welsh Manufacturing Industry in different ways:
- Saving money: Keep the number of prototypes built to a minimum.
- Saving time: Quicker time to market with optimum designs.
- Increasing innovation: Test innovative alternative technologies that could turn out to be game-changers.
- More insight: More information could be obtained from the current process which could inform future directions for product improvement or new product development.
How Is/Can CFD be Done Remotely?
ASTUTE 2020’s modelling capabilities are supported through advanced computational resources, techniques and bespoke software. These advanced techniques can be applied to a range of manufacturing and product scenarios across a variety of sectors and can be accessed remotely to modify CAD files, create CFD models, run simulations and post-process simulations outcomes.
Through this time of uncertainty, research, development and innovation need to be at the forefront of manufacturers’ plans for future growth. ASTUTE 2020 can collaborate with manufacturers remotely to help save money for costly trial and error scenarios, de-risk change and future proof businesses.
How Is ASTUTE 2020’s Expertise Incorporating This Technology into The Welsh Manufacturing Sector?
Illustration of Calon’s MiniVAD™ implanted into the heart’s left ventricle (left) and the full MiniVAD™ system: pump, controller including monitoring devices, batteries and cable (right).
Heart Failure is a condition when the heart becomes less effective in pumping blood around the body. Heart failure affects 26 million people globally. In the UK there are 1 million heart failure cases of which 150,000 are ‘advanced heart failure’ and every year 60,000 new cases are diagnosed. Heart failure is the leading cause of death in the developed world.
There are several treatment methods for heart failure including drugs, devices such as pacemakers, or surgery which includes heart transplant and ventricular assist devices (VADs).
Calon Cardio-Technology Ltd. was founded in 2007 and is developing the next generation of implantable blood pumps for the treatment of advanced chronic heart failure, the MiniVAD™, Miniature Ventricular Assist Device.
A VAD is an electromechanical pump that is used to assist the cardiac circulation in people who have failing hearts. VADs can dramatically improve the quality of life of advanced heart failure patients. Wheelchair-bound patients can drive, cycle, take long walks and even go back to work within a few months. There are three types of VADs in use:
- LVADs: pump blood from the left ventricle to Aorta – most common type. (Calon’s MiniVAD™ is an LVAD.)
- RVADs: pumps blood from right ventricle to Pulmonary artery
- BiVADs: Used with both ventricles
There are different uses for VADs, they can be used in patients who are:
- Recovering from heart surgery or heart attack, “bridge-to-recovery” (short term).
- Waiting for a heart transplant, “bridge-to-transplant” (short term).
- Not eligible for a heart transplant, “destination therapy” (long term).
Calon’s MiniVAD™ is designed to be a destination therapy device and Calon is committed to applying novel technologies and designs to produce a VAD with clear advantages over existing approaches including less invasive surgery, low blood damage, reduced thrombus formation and a control system optimized for quality of life.
Risks and Opportunities
VADs are Class III medical devices and have a high risk to the patient because they are in contact with the patient’s blood. These risks include inflammation, infection and thrombosis. Being a Class III medical device means VADs are subject to rigorous regulatory controls both pre- and post-market. In addition to the above risks to the patient there are business risks to the enterprise should their device cause severe problems to the patient. To mitigate these risks extensive lab experiments were conducted to measure the VAD’s hydraulic and haemolytic performance coupled with advanced CFD simulations to build models of the pump as realistic as possible.
In the current COVID-19 situation, experimental work has halted and this created an opportunity for CFD to fill in the experimental gap and carry on the work needed to optimise the performance of the pump using models developed earlier and validated by previous experimental work. Since CFD work can be done remotely simulations could be performed whenever needed. The simulations helped Calon achieve the following goals:
- Suitability: provide the required blood flow rate to a wide range of patients at different activity levels (e.g. sleeping, reading, exercising).
- Reliability: operate consistently 24/7 potentially for the life of the patient.
- Stability: provide near-silent and vibration-free operation.
- Size: very small and light to fit comfortably in the heart and chest cavity.
- Cost: substantially reduce the cost of manufacturing.
- Blood damage: reduce the risk of blood damage and thrombus formation.
You can find out more about the research ASTUTE 2020 has been conducting with Calon Cardio-Technology here.
ASTUTE 2020 can support manufacturing companies across a variety of sectors, such as aerospace, automotive, energy generation, oil and gas, medical devices, electronics, foods, etc., stimulating growth by applying advanced engineering technologies to manufacturing challenges driving cutting-edge research and innovation. ASTUTE 2020 collaborations inspire manufacturing companies to improve and streamline their manufacturing processes, manufactured products and supply chain, generating sustainable, higher-value goods and services and bringing them to a global market.
The ASTUTE 2020 operation has been part-funded by the European Regional Development Fund through the Welsh Government and the participating Higher Education Institutions.