The turbopump of the space rocket, as the only high-speed rotating machinery in the important components of the rocket engine, is known as the heart of the liquid rocket engine in the industry.

Its working principle is similar to that of the turbocharger of the automobile, which uses the gas to drive the turbine to rotate and drive the pump to work, pressurize the low-pressure propellant in the rocket tank, and deliver it to the gas generator and thrust chamber for combustion in real time.

Liquid rocket engine turbopumps are designed with an emphasis on light weight and high performance, and many turbopump components are designed to be close to the limits of technological development.

Therefore, in order for a turbopump to be reliable and adaptable to the requirements of a launch vehicle or spacecraft, many aspects must be addressed.

For example, in order to meet performance and weight requirements, turbine pumps must operate at high speeds, which must have bearings and seals that meet the life requirements at high speeds.

In addition, the pump must have induction wheels with high suction performance to reduce the pressure and weight of the tank.

At present, the aerospace institutions that are engaged in kerosene liquid oxygen staged combustion cycle engine engines are Dongtang and Maoxiong.

However, there are many kinds of staged combustion cycle engines, and the hydrogen and oxygen engines used by Sun Country and Mi Li are generally high-pressure supplemental oxygen.

The core of the rocket is the engine, and the core of the engine is the fuel pump, because the rocket engine itself is just a very simple cavity, and the key question is how to provide it with enough fuel.

The way fuel is supplied is the circular way.

The cycle mode of rocket engine, judging from the current development trend, is roughly: extrusion, expansion, gas turbine, electric propulsion.

Gas turbines can be divided into several types, such as gas generators, staged combustion, and full-flow staged combustion.

It is a small engine that is powered by rocket fuel, which is then driven by a turbopump to pump the fuel out.

The gas generator is a gas turbine that takes a portion of the fuel and then drives a turbine pump to pump more fuel to the main engine.

The exhaust gas produced by the gas turbine is directly discharged from the body, and the Merlin engine of SpaceX is based on this principle, because the used fuel does not participate in the secondary cycle, so it is also called open cycle.

More advanced is the staged combustion cycle, where the exhaust gases from the gas turbine are fed into the main engine with other fuels and burned again, avoiding waste.

There are two ways to mix the fuel and oxidizer supplied to the gas turbine: one is fuel surplus, that is, rich burn combustion; One is an excess of oxidant, that is, oxygen-rich combustion.

Among them, the exhaust gas after oxygen-rich combustion flows into the main engine and needs to be supplemented with more fuel, so it is called refueling.

More advanced than the staged combustion cycle is the full-flow staged combustion cycle.

Unlike pumping part of the fuel to drive the turbine, the full flow is where all the fuel is burned once to drive the turbine, which can provide more turbine power, and then burn better when the main engine is mixed.

The Raptor engine now being developed by Space Exploration is this kind of engine, the fuel is methane, and it goes through two pre-combustion chambers of rich combustion and oxy-fuel combustion respectively, and then meets in the main combustion chamber.

High pressure, which refers to the performance indicators of the engine.

The rocket generates thrust by jetting backwards, and the pressure inside the combustion chamber of the engine (chamber pressure) determines the speed of the jet, and the pressure is as high as possible.

And a high room pressure means that the turbopump needs to have enough pressure to get fuel into the engine, so the performance of the turbopump engine will definitely be higher.

The YF100 of the Dongtang Space System has a room pressure of 18 megapascals (1 megapascal equals 10 standard atmospheres), which is a high pressure, and as a comparison, the Merlin engine of the Falcon 9 is less than 10 megapascals.

However, Mi Lijia's stunt is low room pressure and high performance, and the F1 engine of the Saturn V is a low-pressure gas generator cycle.

Unconsciously, Huang Haojie's electric car has arrived at the door of the Hydrogen and Oxygen Engine Research Institute.

Several security personnel hurriedly ran over.

"Boss, I'll go and inform Director Qin immediately."

"No need, I'll just go in."

The Hydrogen and Oxygen Engine Research Institute is located near mountains and rivers, and more than half of the space is in the mountains or underground.

I had already heard Huang Haojie coming, and the director Qin Tongxing hurriedly came over.

"Boss, welcome to come and guide the work."

"Where is the progress of hydrogen-oxygen engine research and development?"

"We are working on a magnetic bearing system."

"Check it out."

"Please follow me."

The group came to a laboratory that was developing magnetic bearings.

A huge electric motor is running like crazy.

"This motor is an experimental machine developed by us using room temperature superconductors and strong magnetic repulsion materials." Qin Tongxing pointed to the motor and introduced.

The turbine system of the space rocket engine is different from the turbine system on the car, which is the power source of the turbine.

Automobile turbine systems can be divided into three types according to power sources: exhaust gas turbines, mechanical turbines, and electric turbines.

As the name suggests, exhaust gas turbines use exhaust gases from exhaust pipes to propel turbines; The mechanical turbine is to use the transmission system of the car to drive the turbine; As for electric turbines, they use batteries to drive electric motors, which drive turbocharging.

The turbine system on the space rocket engine is generally of two kinds.

One is a small engine turbine and the other is an electric motor turbine. The former is more common, and the latter is currently in the research and development stage because it is difficult for the motor to achieve a speed of more than 100,000 revolutions.

The hydrogen-oxygen engine research institute is developing an electric motor turbine system.

"What's the rotation?"

"150,000 revolutions per minute."

Huang Haojie nodded with satisfaction, it is already very rare to be able to achieve this speed.

At present, exhaust gas turbines or mechanical turbines can reach 12~160,000 revolutions per minute.

However, the motor is more than 10,000 revolutions per minute at most, and this is still a DC motor, and if it is an AC motor, it is at most 3,000 revolutions per minute.

Why is the rotational speed of an electric motor so low?

Rotor dynamics determines that when the linear velocity of the rotor reaches a certain speed (such as 150m/s), the centrifugal stress exceeds the strength of the rotor and causes some parts of the rotor to detach.

This is a common problem faced by all high-speed motors.

To put it simply, it is the mechanical strength that limits the rotational speed.

In addition, for brushed DC motors, the high speed leads to serious friction between the commutator and the brushes, and the arc is also significantly increased, and the heat accumulated by the two will quickly burn the brushes.

The bearings at the end of the motor also have a certain speed limit, which makes the speed have a bottleneck.

In other words, it is a matter of materials.

If the material meets the requirements, the rotational speed of the DC motor can theoretically be close to infinity.

Materials science is precisely the strength of Galaxy Technology, so under the application of various new materials, the speed of the electric motor turbine of the Hydrogen and Oxygen Engine Research Institute can reach 150,000 revolutions per minute.

"I'm very glad that you can do this, keep up the good work."

"I won't let the boss and everyone down." Qin Tongxing hurriedly said.

"What is the room pressure in the combustion chamber now?" Huang Haojie then asked.

"21~22 megapascals is the limit, and we expect the speed of the turbine system to be increased to 40~500,000 rpm, so that the room pressure of the combustion chamber can be increased to about 30 megapascals."

"Can the combustion chamber withstand a pressure of 30 megapascals?"

"There is no problem, we have used nano stainless steel materials, which are not only very strong, but also can withstand extreme high temperatures of 2,700 degrees Celsius, and after testing, the combustion chamber of the new material can withstand 59 megapascals is the ultimate pressure." Qin Tongxing explained.

"The speed of the motor is increased, and you can communicate and cooperate with the Institute of Electrical Machinery."

"In this regard, we often communicate and cooperate with them."

"Hmm!"

Huang Haojie, accompanied by Qin Tongxing, continued to inspect the Hydrogen and Oxygen Engine Research Institute.

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