Fig 1.
CAD drawing of the rocket module with the location of the temperature sensor marked.
Fig 2.
Acceleration of REXUS-18 [17].
Table 1.
Characteristic phases of flight.
Fig 3.
Temperature measured during flight [17].
Table 2.
Nomenclature used in this work.
Fig 4.
Physical model of rocket module.
Fig 5.
Finite element model with visible sizes of elements (number of element divisions per line equal to 1).
These were the biggest elements considered and were subsequently used in the optimization procedure.
Fig 6.
Finite element model with visible sizes of elements (number of element divisions per line equal to 8).
These were the smallest elements considered and were used only to analyse element size influence on the solution.
Fig 7.
Finite element model with visible sizes of elements (number of element divisions per line equal to 8), magnified to show smallest elements.
Table 3.
Chosen material properties of Al7075 [24].
Fig 8.
Results of simulations of heat flow subject to constant heat flux.
Table 4.
Comparison of optimization results for test with various moving window lengths.
Fig 9.
Influence of the finite element size (described by number of element divisions per line NDIV) on average temperature error ΔT and computation time.
Table 5.
Comparison of calculations for various finite element sizes.
Fig 10.
Temperature distribution.
Fig 11.
Heat flux distribution.
Fig 12.
Determining the reaction time of the studied system.
Fig 13.
Moving window optimization flowchart.
Fig 14.
Moving window optimization Left: Visualization of three consecutive positions (i = 8—upper, i = 9—middle, i = 10—bottom) of moving window for n = 16, k = 3. Right (corresponding to left): linear interpolation of heat flux q values is visible. Points indicate time spans s.
Fig 15.
Comparison of test optimization results for with various moving window lengths k.
Fig 16.
Comparison of test optimization results with various division of heat flux q into time spans s.
All calculations were performed with window length k = 4.
Fig 17.
Calculated heat flux q and temperature T against variables measured during flight: Temperature Y (used for IHTP), pressure, altitude.
Vertical lines indicate characteristic phases of flight, see Table 1 for details.
Fig 18.
Schematic view of the planned experiment to measure heat flux on sounding rocket skin.
Note that insulation was not shown here.