At Experiqs, we believe that the future of space propulsion lies in the Aerospike nozzle. This innovative technology not only promises improved performance over traditional rocket nozzles but also introduces new possibilities for precise thrust control and adaptability across varying atmospheric conditions. To fully explore its potential, our team has conducted a comprehensive computational study of Aerospike nozzles, focusing on their performance and thrust vectoring capabilities. This blog will take you through our findings and how they pave the way for a new era of space travel.
The Importance of Computational Analysis
In aerospace engineering, computational studies are essential for understanding the behaviour of complex systems like the Aerospike nozzle. Through simulations, engineers can evaluate how different designs perform under various conditions without the need for costly physical tests. This is especially valuable for advanced technologies still in the development phase, as it allows for the exploration of multiple configurations and design optimizations
Our computational fluid dynamics (CFD) study focused on two key types of Aerospike nozzles:
- Linear Full-Length Plug Nozzles (LFPN)
- Linear Truncated Plug Nozzles (LTPN)
These two configurations were compared against traditional Convergent-Divergent (CD) nozzles, focusing on thrust performance and efficiency across varying altitudes.
Figure 1 : Schematic of different types of plug nozzles
Source : Vivekanand Nagaral, Rohith R, and Gopalakrishna Narayana, “Study of Aerospike Nozzle and its Thrust Vectoring Characteristics”, 25th AIAA International Space Planes and Hypersonic Systems and Technologies Conference, May 28 – June 1, 2023, Bengaluru, Karnataka, India
Tools and Methods
For our analysis, we employed Reynold’s Averaged Navier Stokes (RANS) turbulence modeling along with the open-source solver SU2. This combination allowed us to simulate the flow of gases through the nozzles at different pressure ratios and altitudes. Using these tools, we could precisely model the complex physics involved in the operation of both the LFPN and LTPN configurations.
The results of these simulations provided valuable insights into the performance characteristics of Aerospike nozzles:
- The LFPN configuration produced higher thrust, making it a strong candidate for missions where raw power is essential.
- The LTPN, on the other hand, demonstrated a better thrust-to-weight ratio due to its reduced mass, making it more efficient for missions where weight optimization is critical.
Thrust Vectoring: A Critical Capability
One of the most exciting aspects of the Aerospike nozzle is its potential for thrust vectoring—the ability to direct the exhaust flow and control the spacecraft’s trajectory. This capability is crucial for modern spacecraft that require precise maneuverability, especially during ascent and docking operations. Our study explored two primary methods of thrust vectoring:
- Fluidic Thrust Vectoring: This method involves introducing a secondary flow into the primary exhaust to alter its direction. Our simulations showed that fluidic thrust vectoring is effective for smaller spacecraft but may not generate sufficient lateral force for larger vehicles. It offers the advantage of a simpler design without mechanical parts, reducing the spacecraft’s overall weight.
- Differential Thrust Vectoring: This technique involves varying the pressure between multiple thrusters to create a side load, altering the spacecraft’s trajectory. Differential thrust vectoring offers greater control for larger vehicles but requires a more complex design involving multiple thrusters.
Both methods have their merits, and our study demonstrated that they can significantly enhance the maneuverability of spacecraft equipped with Aerospike nozzles.
(a) Mach contour of LFPN for fluidic thrust vectoring method for ms =0.5 kg/s
(b) Mach contour of LTPN for fluidic thrust vectoring method for ms =0.5 kg/s
Figure 2 : Fluidic thrust vectoring method for LFPN and LTPN Aerospike nozzles.
Source : Vivekanand Nagaral, Rohith R, and Gopalakrishna Narayana, “Study of Aerospike Nozzle and its Thrust Vectoring Characteristics”, 25th AIAA International Space Planes and Hypersonic Systems and Technologies Conference, May 28 – June 1, 2023, Bengaluru, Karnataka, India
The results of fluidic thrust vectoring for LFPN and LTPN are shown in Figure 3. The Mach contour when no thrust vectoring is applied clearly shows the difference in the jet trail. In the case of fluidic thrust vectoring, the secondary inlet acts as an obstacle to the incoming primary flow. Since the primary flow is supersonic, flow deceleration occurs in front of the secondary inlet, accompanied by flow deflection. In LFPN, the deflection is less significant, allowing the flow to continue with minimal changes to the primary flow. However, in LTPN, the deflection is more pronounced due to the placement of the secondary inlet further from the spike’s tip, leading to more significant flow alteration.
Challenges and Future Outlook
While the results of our computational study are promising, there are still challenges to overcome before Aerospike nozzles can be widely adopted in real-world applications. One of the biggest challenges is the complexity of manufacturing these nozzles. The sharp corners and extreme temperatures involved in the operation of Aerospike nozzles require advanced materials that can withstand harsh conditions. Although modern material science is advancing rapidly, the development of materials capable of handling these stresses is still ongoing.
Despite these challenges, we are confident that Aerospike nozzles represent the future of space propulsion. As technology continues to evolve, the potential for these nozzles to enable Single-Stage-to-Orbit (SSTO) flights becomes more realistic. SSTO missions, in which a spacecraft travels from Earth to orbit without needing to jettison parts of the rocket, could revolutionize space travel by drastically reducing launch costs and improving the reusability of space vehicles.
Conclusion
Our computational study has demonstrated the superior performance of Aerospike nozzles, both in terms of thrust generation and adaptability across varying altitudes. With further research and development, we believe that this technology will play a pivotal role in the next generation of space exploration. Stay tuned for more exciting updates as we continue to push the boundaries of propulsion technology!
