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Thermal Investigation for Accurate Temperature Measurement

Thermal Investigation for Accurate Temperature Measurement. Team TCTJ Truc Le Cedric Toguem Jonathan Newman. Overview. Mission Goal Objectives Science Background Technical Background Payload Design Electrical Software Mechanical Payload Development. Mission Goal.

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Thermal Investigation for Accurate Temperature Measurement

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  1. Thermal Investigation for Accurate Temperature Measurement Team TCTJ Truc Le Cedric Toguem Jonathan Newman

  2. Overview Mission Goal Objectives Science Background Technical Background Payload Design Electrical Software Mechanical Payload Development

  3. Mission Goal The goal is to determine why previous LaACES payloads failed to correctly measure temperature in comparison to NOAA.

  4. Objectives Determine the effect of the thermal boundary layer on temperature measurements Determine the effects of material and coating of temperature sensors on temperature measurement Have the measurements of the control temperature sensor be similar to NOAA measurements

  5. Temperature change in the Atmosphere Troposphere (0 to 12km) : lowermost atmosphere where temperature decreases from 30 to -80°C Stratosphere (12 to 48km): second lowermost part of the atmosphere where temperature increases from -80 to 0°C http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html

  6. Boundary Layer http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html Thin layer of fluid in contact with a solid body that flows more slowly than the rest of the fluid As the payload gains altitude in fluid air, the boundary layer around it will be affected by heat transfer processes

  7. Heat Transfer Modes Heat can be transferred in three different ways: - Conduction - Convection - Radiation

  8. Radiation Electromagnetic radiation emitted from the surface of an object in the form of heat due to the objects temperature If an object is warmer than its surrounding environment, it will emit more radiation in the form of heat into the surrounding environment than it will absorb in order to attain thermal equilibrium http://www.tsc.com/irgen/Image7.gif

  9. Test 1: Radiation Test 1 Radiation test: Sun →Electromagnetic radiation → Space →Sensors The test will consist of different color shielding to reflect the electromagnetic radiation from the sun http://image.tutorvista.com/content/dispersion

  10. Test 2: Radiation Test 2 Radiation Test: • The payload circuitry will emit radiation to the sensor. • Distance from the radiation source will determine the amount of heat dissipated http://images.google.com/imgres?imgurl=http://www.uos.harvard.edu/images/ehs/radiation

  11. Test 3: Boundary Layer Test Sensors are placed at different distance from the exterior surface of the payload Determine how much effect the boundary layer has on the measured temperature http://www.google.com/imgres?imgurl=http://www.engineering.leeds

  12. Sensors 7 temperature sensors Model: 44003RC Precision Epoxy NTC Thermistor -80 °C to 50 ° C 1kΩat 25 ° C

  13. Sensors 1µA constant current from LM134 Output voltage will then vary from 1mV to 190.8mV (Value based on device’s datasheet – Resistance V. Temperature Table)

  14. Sensor Interfacing Sensors’ output voltage will vary from 1mV to 190.8 mV Payload ADC, from 0 to 3V Will use AD820 op-amp to amplify each sensors’ output

  15. Sensor Interface

  16. Sensor Interface Vref = 1V, R6 = 1kΩ R4 = 0.94MΩ R5 = 14.806kΩ

  17. Control Electronics

  18. Power Supply 6 x 1.5V Energizer L92 Ultimate Lithium (AAA) 9V to BalloonSat 9V to Op-Amps pin 7 1V from BalloonSat’s Voltage regulator to Op-Amp Vref 9V Current sources positive voltage terminal

  19. Power Supply

  20. Power budget

  21. Data Format Table

  22. Flight and Post-Flight Software

  23. Programming Flow Chart

  24. Flow Chart During Flight

  25. Exterior Mechanical Design

  26. Interior Mechanical Design

  27. Weight Budget

  28. Payload Development Plan Mechanical Thermal Testing Boom Testing Attachment prototyping Impact test to find best design to store components Maintain payload within regulation

  29. Payload Development Plan Electrical Design the circuitry of the system Determine how well the components will function in flight climate Determine methods of calibration of the sensors

  30. Payload Development Plan Software Determine if extra memory will be needed and how to access it Determine how to access ADC Determine methods of calibration

  31. Reference • Clavius: Environment - heat transfer. http://www.xmission.com/~jwindley/heatxfer.html. November 24, 2009 • Anne E. Egger "Earth's Atmosphere: Composition and Structure," Visionlearning Vol. EAS 2003. http://www.visionlearning.com/library/module_viewer.php?mid=107 • Sad Dr Rodrigue – Introduction to physical Geaography. http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html • BASIC Stamp 2p 24-Pin Module. http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/ProductID/7/List/1/Default.aspx?SortField=UnitCost,ProductName. November 25, 2009

  32. Questions?

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