Project: Venturi Water Nozzle

thingiverse

The venturi water nozzle project can be used to demonstrate physics and engineering. A high speed jet of air creates low pressure suction which will suck water up through the connector and mix with the air stream to come out the nozzle.https://www.youtube.com/watch?v=vrLS9ymRUuw Print Settings Printer: Generic Prusa i3 Rafts: No Supports: Yes Resolution: 0.2mm Infill: 100% Notes: I printed in several orientations to find the one that worked best for my printer. Use supports to help with the floating pieces before they get printed together. Project: Venturi Water Nozzle Overview & Background 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. Accessories 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) water and open vessel graduated cylinder to measure water straw from fast food or your pantry optional - 10' length of 1/4" vinyl tubing (check plumbing section of diy store) calipers, rule, or tape to measure things stop watch protection gear - eye protection!! and any other gear that might be a good idea. 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 suction. Learn how to test and calculate the suction pressure. Audiences Main application: High school physics, college physics lab, fluid dynamics. Really any age could benefit from this project. The demonstration could enlighten all ages. Subjects Physics Science Mathematics Engineering 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. Lesson / ActivityStep 1 - Background Knowledge Discuss Bernoulli's principle and equation. Discuss nozzles. Discuss Ventrui Effect through special nozzles. Print and use the Water_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 below Air source -> hose -> air gun -> water nozzle -> straw / tubing -> water vessel -> anemometer at outlet of nozzle (but you might wait for the anemometer)SAFETY NOTE: start with air gun in closed position and air source off if possible Try it without water first. Turn on air and gun (30 psi seems to work). Measure air speed and take notes. Turn off air and gun. add measured amount of water to water vessel. Turn on air and gun (30 psi seems to work). Time the duration of operation. Measure air speed and take notes. Turn off air and gun. Measure remaining water, or hopefully stop the time when vessel is empty. Option 2: Do above several times with different air pressures: 30 psi, 40 psi, 50psi, etc... Option 3: use length of 1/4" tubing and determine how much elevation head in inches of h2o you can achieve with this nozzle by elevating the nozzle until the flow from the vessel stops. Option 4: Skip measuring and demonstrate the nozzles ability to mist water. Step 3 - Calculations Calculate the air flow through nozzle. Calculate the water flow through nozzle. Calculate the water flow gained or lost at different operating pressures 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. If you did the pressure head, calculate how many inches of h2o the system was able to achieve. 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 venturi nozzle without water? What is the volume air flow through the venturi nozzle with water? Did the air flow change? Why do you think it did or did not? What is the suction pressure? Tips & Tricks It works! It sucks water quite efficiently! Other fluids can work, or even granular material like sand. I used fast food straws for the demo video. I tapered the fluid connection in the design to adapt a variety of tubing diameters. The tapered inlet may need a little attention to smooth it out depending on how you print it. Some of the air gun holders might break off, doesn't effect performance noticeably. Assets I have included the water_nozzle_v3.f3d fusion 360 design file in the thing files. Modifications for other pipe sizes, nozzle sizes, blow guns, air sources, etc... could be made. water_nozzle_v3.f3d water_nozzle.stl water_nozzle_section.stl References https://en.wikipedia.org/wiki/Venturi_effect https://en.wikipedia.org/wiki/Bernoulli%27s_principle https://www.washingtonpost.com/local/a-lip-smacking-look-at-the-day-that-drinking-straws-got-bigger/2013/07/07/f3fd8b8e-e584-11e2-aef3-339619eab080_story.html Nozzle on Gun, straw in water, ready to plug together and spray water.