The Rise of the European Emperor

During the autumn harvest of 1502, Marin was in the cornfield and had commissioned Leonardo to develop a steam engine. At that time, Marin drew a schematic diagram of a steam engine, gave it to Ada, and let it go.

Now, more than a year later, Marin just remembers that the Tara lead-zinc mine is as deep as 50 meters and may need to be pumped. Therefore, Da Vinci's steam engine is very important.

In any case, mechanical pumping is always much faster than human pumping, even if it is the lowest-level steam engine. In fact, in the early days, in the late 17th and early 18th centuries, steam engines were used to pump water for coal mines, and nothing else.

It was not until later that Watt improved the Newcomen steam engine, using a separate condenser and circulation system to reduce water consumption. Moreover, a set of "sun and planet" crank gear transmission system was also developed to convert the reciprocating motion of the steam engine into rotational motion, laying the foundation for the steam engine to become a power engine...

"Oh, sorry, I didn't give Ada the drawing of the 'Sun and Planets' crank gear transmission system. No wonder he hasn't produced results yet..." Marin patted his head regretfully, remembering that he forgot to put the steam engine The very important transmission system that converts reciprocating motion into rotational motion is drawn to Leonardo da Vinci.

No matter how clever Leonardo was, he was only a man from the middle of the 15th century to the beginning of the 16th century. Because of the ideological constraints of the Holy See, he did not dare to exchange advanced scientific knowledge with others, and some behind closed doors might not be able to come up with this transmission system.

At that time, because of a lot of things, Marin wanted to fight against Denmark, and the schematic diagram of the steam engine he drew was the most primitive single-cylinder vertical steam engine. Moreover, only the cylinder block of the steam engine is drawn and the principle of piston movement is simply annotated. The rest are not involved. It is estimated that there is trouble with Ada.

Sure enough, when Marin rushed to Da Vinci's laboratory, what he saw was a very dirty steam engine swaying up and down, and the running speed was oscillating up and down there very slowly. As for what crank-gear drivetrain, that's not there.

Da Vinci was frowning, thinking about how to make the steam engine run faster. Because, as Marin told him at the time, the machine should be turned and run very fast.

This is also a problem of Marin's understanding. In fact, in modern times, whether it is an electrical appliance or an internal combustion engine, the rotation speed is very fast.

However, in the early days of the steam engine, the speed of the steam engine was very slow. The steam engine invented by Watt is much more efficient than the Newcomen steam engine, but the speed is only forty or fifty revolutions per minute. In the modern times before Marin's crossing, an electric fan could turn 500 to 1500 rpm casually, which is completely incomparable. Even in the early 20th century, steam engines did not reach 100 to 300 revolutions per minute. So, it was Marin who was demanding, not that Leonardo wasn't doing enough.

then,

Da Vinci explained the structure and principle of the steam engine he made to Marin in great detail...

The principle of this steam engine is very simple, that is, the steam at the bottom of the boiler burns straight up. When the steam reaches a certain concentration and forms a certain air pressure, it will break through a movable valve at the top, enter the upper cylinder, and push the piston at the bottom to the top.

When the piston is pushed to a certain height, there is an opening in the side of the cylinder, which allows the high pressure steam to escape. In this way, the air pressure in the cylinder is released at once. Under gravity, the piston will fall back. At the same time, the valve between the boiler and the cylinder is also closed.

When the piston falls together, one end of a similar balance rod connected to the top of the piston will be driven by the piston to make a wooden rod at the other end move up and down. Of course, if there is a "sun and planet" crank gear transmission system invented by Watt, the connecting rod will not move up and down in a straight line, but will drive a wheel to rotate through the transmission system.

In addition, because the piston rises to the top, there will be an opening to release all the steam. And water vapor is formed by the vaporization of water. Therefore, the water in the boiler is also reduced with the release of water vapor. Without water replenishment, the boiler could dry out and explode.

Therefore, Da Vinci designed a water supply system on the side of the bottom of the cylinder. There is also an active valve in the pipeline of this water supply system. Moreover, the water container of the water supply system is set high and has a certain water pressure. When the pressure in the cylinder is high, the valve of the water supply system is closed. However, when the piston rises to the top and the steam in the cylinder is suddenly released, the air pressure in the cylinder plume drops sharply. At this time, the water pressure of the water supply system exceeds the air pressure of the cylinder, and then the valve is loose, and a small amount of water will be ejected into the cylinder, and then pressed into the boiler by the piston, which is regarded as adding water.

After listening to the introduction of the whole structure, Marin found out that this is a Newcomen steam engine...

That said, the design is indeed ingenious. However, there is a problem, that is, adding water to the boiler, in fact, cannot be added on it. Because the steam in the boiler is formed by the water surface. Adding water from above will inevitably reduce the temperature of the upper surface of the water in the boiler, affecting the generation of steam.

Therefore, Marin remembers that the steam circulation system of later generations is generally located at the lower side of the boiler to add water to the boiler. In this way, the temperature of the uppermost layer of the water in the boiler will not be lowered, and the production of a large amount of water vapor will not be affected.

The disadvantage of the Newcomen steam engine is this. Adding water from above will reduce the temperature of the surface hot water and reduce the generation of water vapor. As a result, the amount of water vapor in the steam engine is affected, and the power and speed of operation are reduced.

Later, adding water from the side and below can not only avoid the problem of lowering the temperature of the surface water. Also, adding cold water below, closer to the combustion chamber, also heats it up more quickly.

"Yes, the water vapor circulation system..." Marin patted his head and remembered the shortcomings of this steam engine.

Watt's transformation of the Newcomen steam engine, the most important is two points - the first is to add a "sun and planet" crank gear transmission system, so that the operation of the steam engine, from reciprocating motion, into practical rotation; the second is , adding a water circulation system with a separate condenser.

When the water vapor at the upper end of the steam engine leaks out, it is not directly discharged into the air, but passes through a pipe and enters a condenser surrounded by cold water. In order to increase the cooling contact area, the pipes immersed in the condenser water are generally designed to be curved to enhance the condensation effect of the condenser. Moreover, the water in the condenser is changed frequently. Once it's hot, it's replaced with cold water. Moreover, the condensing water is not very demanding, any water can be used, and seawater can also be used. Unlike boiler water, clean fresh water is generally used to prevent scaling from affecting efficiency.

After the water vapor condenses into water in the condenser, it will pass through a pipe and connect to the bottom of the boiler side, and send the cooled water into the boiler to form a cycle. In this way, the water in the boiler is basically not lost. The boiler does not need to be filled with water frequently from the outside. After all, adding water from the outside can easily cool down the heated boiler and affect the efficiency of the steam engine.

However, it does not mean that with this condensing circulation system, there is no need to add water. Because the piston of the cylinder is not 100% sealed. When doing work, a small amount of steam will escape from the gap between the cylinder and the piston.

So, even with the condensing cycle system. After a period of time, the boiler still needs to add water from the outside. Just like the old green-skinned train, when it stopped at the station, it was often necessary to add water. The boiler water should be added, and the cooling water should also be added.

Therefore, in order to prevent the boiler from exploding, the side wall of the boiler generally uses high temperature resistant glass or other instruments to display the water level in the boiler. Once the water level in the boiler has dropped to a dangerous level, in order to prevent an explosion, it is necessary to temporarily shut down and fill the boiler with water.

Marin told Da Vinci the two important improvements of Watt's steam engine that his physics teacher in junior high school taught him, and he was dumbfounded. Then, the old man looked up to the sky and sighed:

"The old man always thought he was the smartest person in the world, but I didn't expect that the guy named Watt was even better than the old man..." Da Vinci's eyes were actually wet. Obviously, this thing was hit.

Marin suppressed a smile and said to Da Vinci:

"Okay, Ada, don't be discouraged. Everyone has their own specialties. That Watt, that is, a steam engine, is better than you. You must be better than him in painting!"

Hearing what Marin said, Da Vinci, who was hit hard, felt better. Then, according to Marin's ideas, the steam engine was "watted"...

However, Marin clearly remembers that there is a centrifugal governor on the Watt steam engine, which is used to control the speed of the steam engine to stabilize.

However, Marin's junior high school physics teacher in his previous life didn't teach this principle, so Marin didn't understand either. After all, he didn't graduate from the Department of Mechanical Engineering, he was just a good liberal arts student in physics.

As a result, the speed of the steam engine may be somewhat unstable. But who cares, the steam engine requirements are not high, and the speed is unstable and unstable.

But in line with the principle of "being the best", Marin briefly explained to Da Vinci the principle of the centrifugal governor, which is probably a cone pendulum connected to the steam valve to control the speed of steam output... Anyway , Marin left this problem to Da Vinci... As for the superiors, they have to learn to leave the problem to their subordinates... If you do everything yourself, it will definitely be the end of Zhuge Liang's overwork...

When the watt steam engine came out, it would be easy to use it to pump water. At that time, Marin will take out the Archimedes screw and make it into a screw pump, which will be used to pump the groundwater of the Tara lead-zinc mine. It should not be too practical...