Development of a three-dimensionalthermal analysis tool for sounding rockets

Detta är en Master-uppsats från KTH/Maskinkonstruktion (Inst.); KTH/Maskinkonstruktion (Inst.)

Sammanfattning:

This thesis has been performed in collaboration with the Swedish Space Corporation at the

department Science Services. SSC provides services in the areas of spacecraft subsystems,

ground stations and sounding rockets to enable governments, companies and research institutes

to benefit from space. Science Services are responsible for sounding rocket flight missions

allowing customers to perform research in a microgravity environment. Currently, they have

good knowledge how to design the sounding rockets experiment modules to minimize thermal

effects within the system. However, no computational models are available to evaluate and

verify the thermal heat transfer inside of the modules and as such the systems are designed

primarily based on previous experience.

The main purpose of this thesis was to develop a thermal computational model, which would

work as a basis for designing experiment modules. The model would be used in an early stage of

the design process before CAD parts have been designed. This required a flexible model

allowing the user to evaluate different types of components and configurations.

A finite element method (FEM) was used to perform heat transfer calculations in MATLAB. The

development process was divided into three stages, which reduced the complexity of the problem

formulation. The first version was made to approximate heat transfer solution in three

dimensions

using the Galerkin’s weighed residuals method. The second version was made to

implement the dynamic environment occurring during flight missions. Based on the external

environment, the dynamic process was divided into phases with different boundary conditions.

In the final version internal convection, conductivity between air elements and a GUI was

developed. The versions were verified with COMSOL (2013) and previous measured flight data.

The results from the simulations showed that the internal convection coefficient and the

element’s conductivity have a great impact on how the heat is distributed inside th

e modules. A

low convection will lead to internal temperature peaks, which can cause damage to sensitive

experiment equipment. Also, the results indicated that the external environment does not have a

significant impact on the internal temperatures. The assumptions made and recommendations are

also covered in this thesis.

Keywords: Three-dimensional heat transfer, Finite element method, Sounding rocket,

Computational simulation

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