HOLDING AN EXPLOSION at 20,000 fps - Smarter Every Day 156

TL;DR

This video explores the combustion dynamics of a transparent potato gun by igniting it from the back and the middle, revealing the different patterns of combustion and providing insights into the venting of a combustion chamber.

Transcript

Hey, it's me Destin. Welcome back to Smarter Every Day (SED). So excited about this video In the last episode of SED I showed you my transparent potato gun, at 3,000 fps during the day. 3, 2, 1 But this episode it's going to be the same transparent potato gun, meaning we can look directly into the science at night, at 20,000 fps. Google up! Science... Read More

Key Insights

• 🫢 Igniting the potato gun from different points results in different combustion patterns, demonstrating the importance of ignition location in the expansion of gases.
• ⛽ Unburned fuel can occur in the combustion chamber when the fuel/air mixture is imbalanced, leading to pockets of fuel that only burn when fresh oxygen is reintroduced.
• 😎 Sidewall cooling in a combustion chamber contributes to unburned fuel and pollution.

Questions & Answers

Q: What is the purpose of igniting the potato gun from different points?

By igniting the potato gun from the back and the middle, the video aims to observe and compare the combustion patterns and understand the effects of ignition points on the expansion of gases.

Q: What causes unburned fuel in the combustion chamber?

Sometimes, when the fuel/air mixture is not perfectly balanced, combustion can run out of oxygen before burning all the fuel, resulting in pockets of unburned fuel and rarefaction that pulls more oxygen back into the chamber.

Q: What is sidewall cooling?

Sidewall cooling refers to the phenomenon where the pipe of a combustion chamber cools the gases below the combustion point, preventing them from burning next to the wall. This leads to more unburned fuel and contributes to pollution.

Q: How does venting dynamics affect the combustion process?

The venting dynamics of a combustion chamber directly impact the creation of localized pressures and rarefactions, which influence the efficiency and combustion patterns of the fuel/air mixture.

Summary & Key Takeaways

• The video showcases the transparent potato gun being ignited from the back, revealing a wave-like combustion that travels from one end to the other.

• The potato gun is then ignited from the middle using electrodes, resulting in a more even combustion and the discovery of sidewall cooling.

• Through slow-motion footage, the video demonstrates how the combustion process relies on oxygen, fuel mixture, venting dynamics, and the need for fresh oxygen to reignite unburned fuel.