thermal investigation for accurate temperature measurement
DESCRIPTION
Thermal Investigation for Accurate Temperature Measurement. Team TCTJ Truc Le Cedric Toguem Jonathan Newman. Overview. Mission Goal Objectives Science Background Science Requirements Technical Background Technical Requirements Staffing Plan Scheduling. Mission Goal. - PowerPoint PPT PresentationTRANSCRIPT
Thermal Investigation for Accurate Temperature Measurement
Team TCTJTruc Le
Cedric ToguemJonathan Newman
Overview•Mission Goal•Objectives•Science Background•Science Requirements•Technical Background •Technical Requirements•Staffing Plan•Scheduling
Mission GoalThe goal of team TCTJ is to accurately measure atmospheric temperature at altitudes up to 35 km with a payload traveling at 1000 ft/s. The goal is to investigate why previous LaACES payloads have failed to correctly make temperature measurements.
Objectives•Accurately measure the temperature of the atmosphere as a function of altitude.•Determine the effect of thermal radiation on temperature measurements
i. Shielding effectii. Distance from circuitry
•Determine the effects of conductivity on temperature measurements•Determine the effect of the boundary layer on temperature measurements
SCIENTIFIC BACKGROUND
Temperature change in the Atmosphere
• Troposphere (0 to 12km) : lowermost atmosphere where temperature decreases from 30 to -70°C• Stratosphere (12 to 48km): second lowermost part of the atmosphere where temperature increases from -70 to 0°C
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html
Boundary LayerThin 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
http://apollo.lsc.vsc.edu/classes/met130/notes/chapter1/vert_temp_all.html
Temperature Change Because of Heat TransferTemperature change in the
atmosphere affects the payload temperature and the payload’s boundary layer
Heat transfer takes place between atmosphere and payload and therefore influences the measurements around the payload
Heat Transfer ModesHeat can be transferred in three
different ways:- Conduction- Convection- Radiation
http://blogs.saschina.org/morena01pd2016/files/2009/10/ccr.jpg
ConductionTransfer of thermal energy between
molecules due to temperature gradient
The energy flows from a region of higher temperature to a region of lower temperature
i.e. From payload to atmosphere in the troposphere and from atmosphere to payload in stratosphere
Convection
Movement of molecules within fluidA shallow layer of air in contact with a
hotter surface warms by conduction, acquires buoyancy and then rises
Affects the air around the surface and can make it different from the air in the atmosphere
RadiationElectromagnetic radiation emitted from the
surface of an object in the form of heat due to the object 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
Science RequirementsThe measured temperature must not
be affected by the heat transfer phenomena around the payload’s boundary layer
To reduce the effect of the payload on the measured atmospheric temperature the thermistors will be placed at a distance away from the payload.
To reduce the effect of radiation from the sun, different shielding will be used.
Technical BackgroundThe goal of the payload design is to
determine the effects of the following on measured temperature:
o Radiation effect from the Suno Radiation effect from the payloado Conduction from the interior/exterioro Boundary layer effect
Technical BackgroundRadiation 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
Technical BackgroundRadiation 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
Technical BackgroundBoundary layer effectSensors are placed at different distance
from the exterior surface of the payloadDetermine how much effect the boundary
layer has on the measured temperature
http://www.google.com/imgres?imgurl=http://www.engineering.leeds
Technical Requirement•The payload will have thermistors that can make measurements at temperature range: 30 to -80˚C•The data will be stored in the B2S24 integrated circuit programmed on an EEPROM on the LaACES BalloonSat.•The data acquisition rate will have three levels with three different rates: 0-10km →sample/394sec10-15km →sample/98sec15-30km →sample/590sec
Technical RequirementPhysical requirements for the payload:
• Operate at pressure ranges : 0 to 1020mb• Operate at temperature ranges: 30 to -
80˚C• Withstand the force of release from
sounding balloon• Withstand impact from landing at 20fps• Stay within FAA no wavier regulations of:
i. Max weight of 500gii. Not exceed 3oz/in2 on any surface
Staffing PlanThe team members that will have the
leads for the major tasks are assigned as such:◦ Project Management: Truc◦ Science Requirements: Cedric ◦ Electronics: Truc◦ Flight Software: Cedric◦ Mechanical: Jon◦ Integration: Truc◦ System Testing: Jon◦ Calibrations: Jon◦ Data Processing and Analysis: Cedric◦ Documentation: Jon
Scheduling
Reference1. Clavius: Environment - heat transfer.
http://www.xmission.com/~jwindley/heatxfer.html. November 24, 2009
2. Anne E. Egger "Earth's Atmosphere: Composition and Structure," Visionlearning Vol. EAS 2003. http://www.visionlearning.com/library/module_viewer.php?mid=107
3. Sad Dr Rodrigue – Introduction to physical Geaography. http://www.csulb.edu/~rodrigue/geog140/lectures/thermalstructure.html
4. 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
Questions• Accurately measure the
temperature of the atmosphere as a function of altitude.
• Determine the effect of thermal radiation on temperature measurements
• Determine the effects of conductivity on temperature measurements
• Determine the effect of the boundary layer on temperature measurements