# Null Space Labs

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thermal_vac_chamber

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 thermal_vac_chamber [2013/08/13 12:13] thermal_vac_chamber [2013/08/13 12:13] (current) Line 1: Line 1: + =====  Project Description  ===== + + In order to simulate the conditions of high altitude flight we must either buy or build our own thermal-vac chamber. Since commercial ones cost more than \$10k, we will be designing, and building our own low cost thermal-vac chamber. + + + =====  Design  ===== + + + + ====  Concept Overview  ==== + + ---- + + + **Step 1** + {{:concept_1.jpg}} + * Place electronic parts into the chamber, minimize thermal conduction (possibly hang parts with fishing strings) + * Close the chamber + * Purge the chamber with dry nitrogen, allow air inside to exit + * Allow the chamber to consist of mostly dry nitrogen + + + **Step 2** + {{:concept_2.jpg}} + * Close off all values to the chamber + * Place dry ice around the chamber to cool the dry nitrogen and electronic parts through thermal convection + * Measure temperature inside the chamber and the temperature of the electronic parts + * Allow it to achieve -60C + + + + **Step 3** + {{:concept_3.jpg}} + * Open the value leading to the refrigerator pump + * Pump the -60C dry nitrogen until the pressure is at 1010 Pa (pascals)  or 0.01atm (1% of pressure at sea level)  (estimate pressure at 100,000ft) + * The chamber is now simulating the environment of 100,000 ft  (-60C and 1010 Pa) + + + + + ====  Mechanical Overview  ==== + + ---- + + + The Thermal Vacuum Chamber concept consists of single 1/4" thick aluminum tube with a 7.5" ID and 8.0" OD. We then place a 1/4" aluminum plate on one end and 1/2" acrylic on the other end. We will also add a hole on the bottom aluminum plate to allow wires to pass. All joints are sealed with low temperature liquid gasket. + + Tubes available here: [[https://www.speedymetals.com/pc-4661-8371-8-od-x-250-wall-tube-6061-t6-aluminum.aspx|https://www.speedymetals.com/pc-4661-8371-8-od-x-250-wall-tube-6061-t6-aluminum.aspx]] + + + Conceptual drawings of the environmental test chamber: + + {{:assm cyl.png?800}} + + + + + + + ====  Mechanical Stress Analysis  ==== + + ---- + + + The following is a stress analysis of one of the walls. It's fixed by the corners and a 14psi pressure load is applied to the wall (at room temperature). Results conclude that deflection is minimal, however more materials should be looked into. + + **Full analysis report:** + Cylinder:  {{:cylinder-simulationxpress study-1.docx}} + + Bottom Plate:  {{:bottom-simulationxpress study-1.docx}} + + + {{:displacement cylinder.png?800}} + + + + + + =====  Electronics  ===== + + * 6 Low Temperature Thermocouples + * Pump Controller + * Pressure Sensor + + + + =====  Software  ===== + + * None
thermal_vac_chamber.txt ยท Last modified: 2013/08/13 12:13 (external edit)