Thermal simulation to assist the design of Aerospace systems

Aerospace systems experience a typical range of temperatures from -250 °C to 300 °C. Given this extremely hot to cold commutation, and vice versa, thermal space simulations are essential to model the thermal protection system. Firstly, the main design of the satellite determines the way and the location heat fluxes (radiation, convection) are entering and moving inside the structure. Secondly, to avoid temperature from rising above the maximum allowable operating temperature, scientific studies based on thermal mechanics of composite materials, so that the structure could withstand these boundary conditions without structural failure. Space Shuttle Thermal Protection System (TPS) is the barrier that protects a spacecraft during the searing heat of atmospheric reentry from friction and temperatures while in orbit. Multiple approaches for the thermal protection of spacecraft are in use among them ablative heat shields, passive cooling and active cooling of spacecraft surfaces.

Figure 1: The command module of Apollo 8 with evident signs of heavy thermal loads

The meaning of a successful mission in space is vital since both human lives and earth resources are ‘’invested’’ to discover the hidden technological opportunities far away of our planet.

Generally, the mechanisms to transfer heat are conduction, convection and radiation.

• Conduction is the energy that transfers across a system boundary due to temperature differences by the intermolecular interaction. In space, thermal analysis heat loads are generated by electronic systems on the PCBs, such as batteries.
• Convection is the transfer of heat between the solid surface and the liquid. Concerning thermal space simulation convection heat transfer is mainly negligible and it is generated in the inside area of the satellite since the energy is traveling through the vacuum of space.
• Radiation is the transfer of heat by electromagnetic waves and does not require the presence of a material medium to take place. The Direct Solar Energy from Sun and the Solar Energy Reflected from Earth are responsible for the major amount of thermal radiation heat.

The mission requirements including operational temperature limits and orbit specifications are essential for thermal analysis. Specifically, orbit type according to altitude classifications (low Earth, Medium Earth, Geosynchronous – Geostationary) and orbit date and positions determine the space radiation.

Simcenter™ 3D Space Systems Thermal software is the space industry vertical application that provides a comprehensive set of tools to conduct orbital thermal analyses within the Simcenter 3D environment. It is ideal for orbital vehicle applications with complex geometry-based models. The solver enables engineers to handle large thermal models with specific thermal features that must be defined to validate the thermal results against the real state problem.

Figure 3: The Orbit Visualizer window  in SImcenter 3D displays the aim, alignment, satellite-sun and satellite planet vectors

The benefits of using Simcenter 3D Space Systems Thermal are summarized below:

• Predict thermal performance for orbiting vehicles accurately and quickly
• Reduce costly physical prototypes by using thermal simulation to understand product performance
• Increase collaboration and team productivity with a thermal analysis solution that is easily integrated with your design and engineering process
• Leverage all the capabilities of the Simcenter 3D integrated environment to make quick design changes and provide rapid feedback on thermal performance
• Maximize process efficiency with a highly automated solution that requires no additional input files and carries out analysis in a single pass

As an engineering office, FEAC ENGINEERING P.C is committed to delivering multi-physics simulation services covering, amongst others, the entire space system development. By utilizing the Simcenter 3D Space Systems Thermal Solver we can solve steady-state and transient models of linear and non-linear problems with great accuracy and consequently guide the design early in the design cycle instead of just verifying it.