We like to imagine that technology develops at a consistent pace, allowing people to confidently predict that “In 30 years’ time we’ll all be in flying cars”. While some aspects of technology perhaps do evolve at a constant rate, in general, politics, regulations, money, and other such mundane things tend to place hurdles in the path of rapid technological progress.
Way back in the 1950s, the US was working on hypersonic flight (primarily to supersede the space shuttle), but it’s taken multiple decades of patchy technological progression and economic stars aligning to reach the point where several private businesses are simultaneously working on operations involving high-speed flight. SpaceX, Virgin Galactic, Blue Origin, Hermeus, and Jaxa are each developing their own hypersonic and sub-orbital aircraft, offering the prospect of reaching anywhere on the planet within 3 hours.
Beyond civilian travel, designing with consideration for hypersonic speeds remains an important aspect of military weapons and space re-entry craft, but are subject to the same challenges of operating under incredibly intense conditions.
Extreme speeds bring new problems
The hypersonic region begins around Mach five (3,705 mph). Standard jet engines with turbines can function into the supersonic range, but at hypersonic speeds, they will disintegrate. While rocket propulsion is generally used in this range, it uses huge amounts of fuel, which adds weight. In the search for less fuel-hungry methods, scramjet and air turboramjet technologies are also being proposed for many new hypersonic projects as they burn compressed atmospheric oxygen. The issue here is that the scramjet needs to be at hypersonic speeds before it will operate, so secondary means are required to get there.
The technical and economic issues developing and building these aircraft are significant – not just propulsion, but also factors such as materials and – however, major benefits can be gained from confronting and overcoming them early on at the design stage. Well before any components are mounted and certainly before any wheels have left the ground, high-performance simulation software can reduce turnaround time and costs by optimizing designs for safe, efficient, and economical flight at hypersonic speeds.
CFD: helping to usher in a new hypersonic era
Computational fluid dynamics (CFD) is a key tool for simulating the incredibly complex physics taking place above the hypersonic threshold. One of the major challenges for designers is aerodynamic heating resulting from the compression of air and intense friction of air at a flying object’s surface are subject to at hypersonic speeds. Deformation and ablation rule out the use of standard metals as they are simply not able to withstand such harsh conditions. Some simulation software also struggles with hypersonic aerodynamic heating, which means it is vital to specify high-performance technology when dealing with these types of applications.
The newly-released Cradle CFD 2022 from Hexagon includes two new features for hypersonic flows for hypersonic vehicles:
- Non-equilibrium thermodynamics (“2-temperature model”) – for predicting extreme fluid temperatures at the leading tip of hypersonic vehicles
- Catalytic wall advanced physics model – for predicting heat transfer from the fluid to the surface during hypersonic flow
Within Hexagon’s Cradle CFD offering, scFLOW is a cutting-edge CFD tool that utilizes an unstructured mesh to accurately represent complicated geometry. With a pre-processor that enables users of all levels to generate high-quality polyhedral mesh elements and a robust, reliable solver that ensures greater stability and much shorter turnaround times, scFLOW is capable of solving aerospace aerodynamics, including within the hypersonic range.
True co-simulation is possible
scFLOW’s immense capabilities are further enhanced when combined with MSC Nastran, Marc, and Adams through the dedicated MSC CoSim engine. Multiphysics coupling has been a functionality often claimed in the past but has perhaps not been delivered with great satisfaction for engineers. Now, with the MSC CoSim engine, true cosim communication between software can be achieved without hard scripting, bringing together separate disciplines within a single hub, again impacting positively on turnaround times and delivering improved results. This tool removes the factor of time lost waiting for assistance from practitioners of separate disciplines and then reformatting the data to allow the software to communicate.
Your partner for hypersonic CFD analysis
Hexagon’s offering for hypersonic CFD analysis is robust and user-friendly, delivering high-fidelity results in short timescales. Built on National Institute of Aerospace (NIA) research, which is headquartered in Hampton Virginia, near NASA Langley Research Center (LaRC), our CFD software is one of the most stable for simulating hypersonic flows, giving you the power and agility to overcome its range of challenges.
This content was originally published on the Hexagon MI website.
