Project: Venturi Air Nozzle

thingiverse

The venturi air nozzle project can be used to demonstrate physics and engineering. A high speed jet of air creates low pressure suction which increases the volume of airflow to a greater amount than in the jet alone. The original intent of the design was to feed air into a charcoal based foundry. Print Settings Printer: Generic prusa i3 style Rafts: No Supports: Yes Resolution: 0.1mm (others may work) Infill: 100% Notes: I printed with 1.2mm shell. I used a 35% infill support to print the blocked nozzle and a 40% infill support for the open nozzle. (These are the settings I used to get the quality I was looking for, YMMV for your printer and intended use) How I Designed This Design notes on this design from my engineering notebook I started out with an inexpensive air blow gun for compressed air and a 1" female PVC fitting. I used calipers to get the main measurements and took notes as shown in my image. Next, I then started drawing a half cross section in Fusion 360. I used a half cross section because I planned on revolving the section around the middle to create the round part. Then, I revolved the sketch around the middle axis. Next, I had to add supports for the now floating nozzle to connect it to the outter tube. Finally, I added some cuts into the blow gun adapter so the gun can snap in. After printing the first design I realized my tolerance for the air gun snap was too tight and made a cut in the input end of the nozzle to make the air gun easier to plug in. Cross section for revolving, drawn in Fusion 360 Standards NGSS CCSS Overview and Background Overview Venturi nozzles are a useful device for increasing air flow or creating a vacuum with a given high speed air source. They have several uses in aviation avionics, jet engines, jet water pumps, atomizers, just to name a few. Students can get hands on experience with a small scale 3D printed nozzle and learn the physics associated with the venturi effect. Bernoulli's principle and equation are stars in this project. Main application: High school physics, college physics lab, fluid dynamics. Really any age could benefit from this project. The demonstration could enlighten all ages. Skills Learned (standards) MP.4 - Model with mathematics. (HS-ETS1-1), (HS-ETS1-2), (HS-ETS1-3), (HS-ETS1-4) RST.11-12.9 - Synthesize information from a range of sources (e.g., texts, experiments, simulations) into a coherent understanding of a process, phenomenon, or concept, resolving conflicting information when possible. References https://en.wikipedia.org/wiki/Venturi_effect https://en.wikipedia.org/wiki/Bernoulli%27s_principle Lesson Plan and Activity Objectives Learn how to calculate moving air volume based on speed and cross section. Learn how high speed air can create pressure differentials. Learn how to utilize air pressure differential to create more air flow. Lesson / Activity Step 1 - Background Knowledge Discuss Bernoulli's principle and equation. Discuss nozzles. Discuss Ventrui Effect through special nozzles. Print and use the Air_Nozzle_cross_section for as a visualization aid. Step 2 - Design and/or build Option 1: Have students design a ventrui nozzle and print it. Option 2: Print the nozzles I have in the thing files. Step 3 - Practical testing Option 1: Assemble the parts as shown: Photo coming soon Air source -> hose -> air gun -> blocked nozzle -> 1" PVC union -> 1" PVC pipe -> anemometer at outletSAFETY NOTE: start with air gun in closed position and air source off if possible Turn on air and gun (30 psi seems to work). Measure air speed and take notes. Turn off air and gun. Swap out nozzle with open nozzle. Turn on air and gun (30 psi seems to work). Now you can use the ribbon, tissue, or smoke to show the suction around the inlet end of the nozzle. Measure air speed and take notes. Turn off air and gun. Option 2: Do above several times with different air pressures: 10 psi, 20 psi, 30psi, etc... Option 3: Skip measuring and demonstrate differences between open and closed nozzle - suction or no suction. Step 3 - Calculations Calculate the flow through each nozzle. Calculate the additional air flow gained by the venturi nozzle. If you did the range of psi tests, graph the results and determine the most efficient air pressure for this nozzle. Step 4 - Review Discuss applications where students might see them. Discuss how students think they could use them in a new application. Rubric What is the velocity of the air for each nozzle? What is the diameter of the outlet? What is the volume air flow through the blocked nozzle? What is the volume air flow through the venturi nozzle? What is the suction pressure? Materials Needed I have included the air_nozzle_v3.f3d and air_nozzle_blocked.f3d fusion 360 design files in the thing files. Modifications for other pipe sizes, nozzle sizes, blow guns, air sources, etc... could be made. air_nozzle_v3.f3d air_nozzle.stl air_nozzle_blocked.f3d air_nozzle_blocked.stl air_nozzle_cross_section.stl The following materials and items can be helpful with this project. compressed air source (could be air compressor, bicycle pump with a surge tank, other source?) air hose with quick release ends Pocket Blow Gun with Industrial Coupler (example: http://www.harborfreight.com/Pocket-Blow-Gun-with-Industrial-Coupler-68262.html) ribbon, tissue paper, toilet paper, or smoke generator (dry ice maybe?) to help visualize air flow 1" PVC union joint any length of 1" PVC pipe to extend your outlet to give students more room to work (Note: longer you go creates more friction losses in your outlet) anemometer to measure air speed calipers, rule, or tape to measure things protection gear - eye protection!! and any other gear that might be a good idea. Project: Venturi Air Nozzle Venturi Nozzle Suction