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LaACES Program Pre-Preliminary Design Review Presentation for the Air Flow Measurement Experiment By Dream Team. Mike Reich Kathryn Gilson David Branch Jared Pellegrin. Outline. 1. Purpose 2. Goals and Objectives 3. Science Background
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LaACES Program Pre-Preliminary Design Review Presentation for the Air Flow Measurement Experiment By Dream Team Mike Reich Kathryn Gilson David Branch Jared Pellegrin Air Flow Measurement
Outline 1. Purpose 2. Goals and Objectives 3. Science Background -Overview of Airflow and Atmospheric Properties -Applications of Wind Speed Measurements Filters High Altitude Power Generating Kites 4. Previous Methodologies and Measurements -Hot-wire Anemometers -Pitot Tubes -Sonic Anemometers -Force and Drag Anemometers 5. Expected Results 6. Conclusion Air Flow Measurement
Purpose • To provide: • an overview of our group’s goals and objectives • knowledge of the science behind our experiment including: • an introduction to the atmosphere and air flow • practical applications for measuring and understanding air flow in the atmosphere • previous methods for measuring the airflow • the expected results of our experiment. Air Flow Measurement
Outline 1. Purpose 2. Goals and Objectives 3. Science Background -Overview of Airflow and Atmospheric Properties -Applications of Wind Speed Measurements Filters High Altitude Power Generating Kites 4. Previous Methodologies and Measurements -Hot-wire Anemometers -Pitot Tubes -Sonic Anemometers -Force and Drag Anemometers 5. Expected Results 6. Conclusion Air Flow Measurement
Goals and Objectives • Mission Goal • To build a high altitude balloon sensor payload to measure wind speed as a function of altitude in order to calculate the mass flow rate of air at different levels of the atmosphere. • Technical Objectives • Complete PDR, CDR, and FRR documentation in accordance with requirements and deadlines established by the ACES staff • Design and construct a balloon payload that: • Is sturdy enough to withstand the harsh conditions of the upper atmosphere • Can measure and store wind speed measurements • Allows for data retrieval when interfaced with a computer using Basic Stamp Air Flow Measurement
Goals and Objectives • Science Objectives • Compute density of air at various altitudes using ideal gas law parameters • Determine wind speed as a function of altitude from measurement data • Compute the mass flow rate of air at various altitudes using the wind speed and density • Compare our results with published findings to determine accuracy Air Flow Measurement
Outline 1. Purpose 2. Goals and Objectives 3. Science Background -Overview of Airflow and Atmospheric Properties -Applications of Wind Speed Measurements Filters High Altitude Power Generating Kites 4. Previous Methodologies and Measurements -Hot-wire Anemometers -Pitot Tubes -Sonic Anemometers -Force and Drag Anemometers 5. Expected Results 6. Conclusion Air Flow Measurement
Overview Of Airflow and Atmospheric Properties • Air flow is a measurement of the amount of air passing through a given region • Affected by pressure, temperature, and other atmospheric forces • Pressure decreases with altitude Plot of pressure versus altitude Air Flow Measurement
Overview Of Airflow and Atmospheric Properties • Temperature decreases until the tropopause • Increases after the tropopause Plot of temperature versus altitude Air Flow Measurement
Overview Of Airflow and Atmospheric Properties • Coriolis forces deflect wind off of its linear path • The strength of the force is dependent on distance from equation Illustration of Coriolis force deflecting wind Figure of Coriolis force varying with distance from equator Air Flow Measurement
Overview Of Airflow and Atmospheric Properties • Upper wind circulation • Surface wind circulation Figure of upper atmosphere wind circulation Figure of surface wind circulation Air Flow Measurement
Outline 1. Purpose 2. Goals and Objectives 3. Science Background -Overview of Airflow and Atmospheric Properties -Applications of Wind Speed Measurements Filters High Altitude Power Generating Kites 4. Previous Methodologies and Measurements -Hot-wire Anemometers -Pitot Tubes -Sonic Anemometers -Force and Drag Anemometers 5. Expected Results 6. Conclusion Air Flow Measurement
Filters • Used to measure concentration levels of various airborne substances • Wood measured amount of radioactive debris in stratosphere • Used propellor anemometer to measure wind speed • Calculated volume of air through filter to give results meaning Wood’s filter and anemometer schematic Air Flow Measurement
High Altitude Power Generating Kites • Developing area of study in wind energy • Kite spins giant carousel arms to produce electricity • Cheaper and more efficient than wind turbines Kite carousel diagram Air Flow Measurement
Outline 1. Purpose 2. Goals and Objectives 3. Science Background -Overview of Airflow and Atmospheric Properties -Applications of Wind Speed Measurements Filters High Altitude Power Generating Kites 4. Previous Methodologies and Measurements -Hot-wire Anemometers -Pitot Tubes -Sonic Anemometers -Force and Drag Anemometers 5. Expected Results 6. Conclusion Air Flow Measurement
Hot-wire Anemometers • Consists of a metal wire that is heated up by an electrical current • Measures air speed by the air’s cooling effect on the wire • There are three types of hot wire anemometers: • Constant-Current • Constant-Voltage • Constant-Temperature Schematic of a hot wire anemometer Air Flow Measurement
Pitot Tubes • Determines air speed by using differential pressures • The velocity of a fluid is related to the pressure and elevation along the fluid streamline by Bernoulli’s equation. Pitottube illustration Bernoulli’s equation Air Flow Measurement
Pitot Tubes • The constant value in Bernoulli’s equation is the same for all points along a streamline of the fluid. • Solving for unknown fluid velocity is show in Equation 2. Equation 1 Equation 2 Air Flow Measurement
Sonic Anemometers • Measure wind speed by using the speed of sound • Sound waves are injected into the air and the change in travel time of the sound wave is dependent upon wind speed Photo of sonic anemometer Air Flow Measurement
Force and Drag Anemometers • The amount of force or drag caused by wind is directly related to the speed of the wind • Can be fixed mounted or vane mounted • Cup anemometer Photo of a vane mounted propeller anemometer Photo of a UVWpropeller anemometer Air Flow Measurement
Outline • 1. Purpose • 2. Goals and Objectives • 3. Science Background • -Overview of Airflow and Atmospheric Properties • -Applications of Wind Speed Measurements • Filters • High Altitude Power Generating Kites • 4. Previous Methodologies and Measurements • -Hot-wire Anemometers • -Pitot Tubes • -Sonic Anemometers • -Force and Drag Anemometers • 5. Expected Results • 6. Conclusion Air Flow Measurement
Expected Results • The expected average wind speed can be found by determining the rate of ascent of the high altitude balloon Balloon ascent rate versus altitude Air Flow Measurement
Expected Results • Approximate theoretical ascent rate governed by terminal velocity force balance: • Drag force is dependent of velocity which allows for calculation of wind speed Terminal velocity equation Free body diagram of balloon Air Flow Measurement
Expected Results • Mass flow rate depends on density, velocity, and cross sectional area • Density changes with altitude • Expect to see a drop in mass flow rate with an increase in altitude Mass flow rate equation Plot of altitude versus density Air Flow Measurement
Outline • 1. Purpose • 2. Goals and Objectives • 3. Science Background • -Overview of Airflow and Atmospheric Properties • -Applications of Wind Speed Measurements • Filters • High Altitude Power Generating Kites • 4. Previous Methodologies and Measurements • -Hot-wire Anemometers • -Pitot Tubes • -Sonic Anemometers • -Force and Drag Anemometers • 5. Expected Results • 6. Conclusion Air Flow Measurement
Conclusion • The purpose of this presentation was: • To establish our group’s goals and objectives • To demonstrate our knowledge of the science pertaining to our proposed experiment which included: • An overview of factors that affect wind speed • Some applications of wind speed and mass flow rate data in order to show the importance of performing our experiment • Previous methodologies and measurements in order to explain ways to measure wind speed and mass flow rate • What we expect from the results of our measurements Air Flow Measurement
Questions? Air Flow Measurement