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thermal_vac_chamber [2013/08/13 12:13] (current)
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 +=====  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)