Chemical Rocket Propulsion Basics
The basics of chemical rockets
The idea of a rocket is pretty simple, just blow stuff up and launch it out the back, but the reason this creates thrust is because of 2 reasons. Before we begin, you have the note that this is only applicable to chemical rockets as ionic thrusters and other types of rockets do not work the same as chemical engines, which are the most mainstream and powerful rocket thrusters.
Firstly, rockets work by heating up a fuel source with oxygen, causing combustion. This combustion creates pressure on the walls of the fuel tank which is one of the causes of rocket propulsion. The pressure on the sides of the rocket cancel out because its in equal pressure in 2 opposite directions. One key feature of rockets is the hole at the bottom of it for the thrust to exit, which in turn creates an imbalance of pressure. The combustion cannot exert a pressure on the bottom since there is a hole, which causes the pressure exerted up to stay because the is no equal but opposite pressure to cancel it out. This upward pressure is a part of the reason why rockets work.
The second reason for rocket propulsion is because of Newton’s laws. When you launch the fuel out of the bottom, you in turn create a force pushing down, and when you push down, you go up. This is because of Newton’s 3rd law of motion in which every action has an equal but opposite reaction; push down, go up. This force is created for 2 reasons, the combustion, and the hole at the bottom. Since the fuel is launched out of the hole, it pushes down, but this pressure is not enough to launch a rocket, so in turn we have to use another principle of science. Whenever you cover up a running hose with your thumb, you create more pressure, since the original pressure is focused to a smaller area. This idea also applies for rockets so, depending in the size of the hole where the fuel exits from, a rocket may go faster or slower. Since the fuels exit is small, the fuel will in turn, speed up to match the smaller area of pressure. This speed will greatly increase the downwards force because of Newton’s second law, force = mass * acceleration.
When both these sources of thrust are combined, they work together to propel rockets into space. chemical rockets are the perfect tool to launch hundreds of thousands of pounds into space and are the holy grail of escaping the atmosphere. These 2 reasons for rocket propulsion are why we landed on the moon, why we have global communication, why we have gps, etc. My goal is to inform you about the intricacies behind rockets, thank you fore reading.