The purpose of the experiment is to make qualitative and quantitative statements about the insulation effect of Cellulose Aerogel fibers. The heat conductivity coefficient is one way of characterizing the insulation effect of materials. It describes the resistance of a material to heat flow caused by temperature deviation on the surfaces of the material. Different methods to determine the heat conductivity coefficient are described in DIN EN 12664 or DIN EN 12667.

One of these methods is the determination with the aid of a measuring plate device for heat flows. Different formats of this device are shown in the figure below.

Drei verschiedenen Anordnungen des Wärmemessplattengeräts

The device consist of a heating plate U´, one or two temperature sensors H, one or two test specimen S and a cooling plate U´´. In order to determine the thermal resistivity the heating plate is heated up until a stationary state is reached. The measured difference in temperature ΔT between the surface of the test specimen and the heat flow Φ can be used to calculate the resistivity in the following way:

The heat flow corresponds to the electrical power supply of the heating plate. During the flight of the high altitude research rocket a stationary temperature condition will not be reached. This and the fact that the heat flow is not determinable make this method not transferable without further ado. However the heat flow can be identified by using a reference measurement with a specimen of a different material with a known thermal resistivity. With

the thermal resistivity of the Aerogel specimen calculates up to:

This equation reveals that the measurement of the thermal resistivity R can be traced back to the calculation of the temperature difference T with the help of a referential measurement.

Furthermore the norm also includes guide lines for a reasonable quantity of temperature sensors and the right installation of the specimen. The quorum of sensors on each side of the specimen should not fall below a value of  and in no case lower than two. This is also important in the case of redundancy of failing sensors during flight.

Since the thermal resistivity cannot be identified during flight, the insulation effect has to be evaluated differently. An easy way to do this is by comparing the insulation effect of the textile specimen with that of other isolation materials. In order to conduct a direct comparison of diverse specimen different materials can be mounted adjacent to each other analog to the method of the heat flow measuring device. Since the ambient conditions such as temperature or pressure are the same for all specimens, the insulation effect can be compared with the help of the measured difference in temperature.

In addition a camera shall be mounted onto the heat shield in order to record the orientation of the rocket at the re-entry. This can help to conclude how the specimens were submitted to the heat and it can be avoided that interesting findings result from a disadvantageous re-entry because one of the specimens was potentially shielded from the heat. The recording is also very useful for our outreach program. This is why the camera shall record the entire flight from start till landing.

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