How the steam engine works and how its energy is converted

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The working principle of the steam engine is a reciprocating power machine that converts the energy of steam into mechanical work.

The water in the steam boiler boils for steam, the steam is sent to the cylinder, enters the slide valve chamber through the main steam valve and the throttle valve, and enters the left or right side of the cylinder alternately under the control of the slide valve, pushing the piston to move, and the steam engine directly converts the up and down motion of the piston into the rotary motion of the ship shaft.

The biggest advantage of the modern steam engine is that it can convert thermal energy into mechanical energy using almost all fuels.

Classification of steam enginesAccording to the steam working on one or both sides of the piston, the steam engine can be divided into two types: single-acting and double-acting;

According to the cylinder arrangement, it can be divided into vertical and horizontal; According to whether the steam is expanded in one cylinder or continuously expanded in multiple cylinders, it can be divided into single expansion type and multi-expansion type; According to the flow direction of steam in the cylinder, it can be divided into return flow type and single flow type;

According to the exhaust mode and exhaust pressure, it can be divided into condensing type, atmospheric type and back pressure type.

The principle of the steam engine is to absorb heat through thermal expansion and contraction, and then release it to a low-temperature heat source, which is to provide power by realizing the temperature change caused by the thermodynamic process.

The function of the steam engine is to convert the internal energy of steam into mechanical energy, the principle is that steam pushes the piston to make a linear reciprocating motion, and then transforms it into rotation through the connecting rod crankshaft, and outputs the rotational torque to do work. Sometimes the reciprocating power is also used directly to do work.

The principle is to convert the energy of steam into mechanical power, so as to ensure the operation of the steam engine, and at the same time promote the development of machinery. According to the working principle of steam, it provides strong power and drives the operation of machinery.

The repeated movement of the piston back and forth in the cylinder by the steam can also be driven by the connecting rod to rotate the flywheel, and the motion will become a circular motion. To put it simply, it is to convert some of the energy of steam into mechanical functions. It was James Watt who improved the steam engine, and he was also a very good industrialist.

The principle of the steam engine is to convert the energy of steam into mechanical work. And this thing was invented by Hiro, who has made a great contribution to us, and many people admire him very much.

It is the use of heat to provide kinetic energy to allow some machines to operate. Hero, his invention was used for a long time, and it was an important achievement of the Industrial Revolution.

It was the steam engine that was modified by Watt that finally generated power through air pressure and finally made the machine move. Hero invented the rudiments of the steam engine.

Watt steam engine, simply put, is the cylinder and the reversing valve, the steam pushes the piston to do repeated movement in the cylinder, drives the flywheel to rotate through the connecting rod, and changes the reciprocating motion into a circular motion, and the flywheel in turn drives the reversing valve, changes the relationship between the intake and exhaust of the piston twice, realizes the automatic reversal of machinery, and maintains the continuous operation of the machine. But this kind of steam engine has been basically eliminated due to low efficiency, and now it is generally used steam turbine technology, that is, it uses high-pressure steam to directly impact the turbine to achieve rotation, just like the principle of windmill, but this kind of steam engine, the technology is complex, and it is only suitable for high-pressure steam, and it is generally used for thermal power stations or nuclear power plants.

In 2010, a new steam engine appeared, that is, a rotary piston steam engine, which was inspired by a rotary piston internal combustion engine, with a triangular piston in an approximate figure-eight cylinder. Using steam instead of gas to drive the piston to rotate the workmanship, which can not only use low-pressure steam, but also have no reciprocating structure, simple structure and high efficiency.

The working process of the steam engine is as follows:1The heat energy of the fuel combustion process boils (gasifies) the water in the boiler, 2The steam produced has a certain pressure, 3The pressure of the water vapor pushes the piston into motion.

Energy conversion of each step:1The chemical energy of the fuel is converted into heat energy through combustion (which is actually a chemical reaction); 2.

The heat energy of combustion is transferred to the water in the boiler (this step is the transfer of energy, there is no conversion); 3.The water vapor produced by the heating gas tung belt of water has a certain pressure, and this pressure is the mechanical energy local liquid reed, that is to say, the heat energy is converted into mechanical energy; 4.The mechanical energy of water vapor propels the machine to work.

The whole process is that the chemical energy of the fuel is finally converted into the mechanical energy that propels the machine to work.

The principle of the steam engine:

The steam engine is mainly composed of cylinder, base, piston, crank connecting rod mechanism, slide valve steam distribution mechanism, speed regulating mechanism and flywheel. The cylinder and base are stationary parts.

In a steam boiler, water is boiled into steam through the combustion process. Through the pipes, steam is sent to the cylinders. The valve controls the time when the steam arrives at the cylinder, enters the slide valve chamber through the main steam valve and the throttle valve, and is controlled by the slide valve to alternately enter the left or right side of the cylinder to push the piston to move.

The steam pushes the piston inside the cylinder to do work, and the cooled steam is introduced into the condenser through the pipe to re-condense into water. This process is repeated constantly while the steam engine is in motion.

When the water in the steam engine boils, the air inside the cylinder expands dramatically, pushing the piston inside the cylinder. （1.Here is the use of energy conversion, from the chemical energy of water into the internal energy of the air, and from the internal energy of the air into the mechanical energy of the piston) The piston drives the axle connected to the back, and the wheels of the car are on the left and right sides of the lever connected to it, so that the car moves.

Because the distance of the piston is too long, the volume of gas in the cylinder increases, the pressure decreases, and the water stops boiling at 1 standard atmosphere pressure (2It is used here that the pressure decreases with the increase of the volume of the gas under the condition of constant temperature. The boiling point of the liquid decreases as the pressure decreases) Through the action of fuel, the water boils again, driving the piston and its axle, so that the car can move in a cycle.

The physical knowledge also includes that the action of forces between objects is mutual, energy is conserved, and the force is applied to the ground. The friction between the tire and the ground, that is, the traction force with the car is a pair of balancing forces.

Animation of how the steam engine works**.

The steam engine works on one or both sides of the piston according to the steam, which can be divided into single-acting and double-acting types; According to the cylinder arrangement, it can be divided into vertical and horizontal; According to whether the steam is expanded in one cylinder or continuously expanded in multiple cylinders, it can be divided into single expansion type and multi-expansion type; According to the flow direction of steam in the cylinder, it can be divided into return flow type and single flow type; According to the exhaust mode and exhaust pressure, it can be divided into condensing type, atmospheric type and back pressure type.

The simple steam engine is mainly composed of cylinder, base, piston, crank connecting rod mechanism, slide valve steam distribution mechanism, speed regulating mechanism and flywheel, etc., and the cylinder and base are static parts. The new steam from the boiler enters the spool chamber through the main steam valve and the throttle valve, and is controlled by the spool valve to enter the left or right side of the cylinder alternately, pushing the piston to move.

The development of the steam engine is first reflected in the increase in power and efficiency, which in turn depends mainly on the improvement of steam parameters. The steam pressure of the initial steam engine was only megapascals, which was only reached in the early 19th century, and 6 10 megapascals were used in the 20s of the 20th century. In terms of steam temperature, at the end of the 19th century it did not exceed 250, and by the 30s of the 20th century it was used 450 480.

As for efficiency, the total efficiency of a steam engine running continuously at the beginning of Watt does not exceed 3 in terms of fuel calorific value; By 1840, the best condensing steam engines had a total efficiency of 8; By the 20th century, the maximum efficiency of the steam engine could reach more than 20.

In terms of rotational speed, the Watt steam engine at the end of the 18th century was only 40 to 50 rpm; At the beginning of the 20th century, the speed reached 100,300 rpm, and some steam engines reached 2,500 rpm. In terms of power, initially a single engine had only a few horsepower, and a marine steam engine at the beginning of the 20th century could reach 25,000 horsepower.

With the improvement of steam parameters and power, it is no longer possible for steam to continue to expand in one cylinder, but also to continue to expand in connected cylinders, so there is a multi-stage expansion steam engine. Due to the limitation of the flash point of lubricating oil, the maximum temperature of steam used in the steam engine is generally not more than 400, and the mobile steam engine such as locomotive and marine is slightly lower, most of which are not higher than 350. Taking into account the possibility of expansion and the economy of the structure, the usual pressure is below megapascals.

The steam parameters are limited, which also limits the further increase in the power of the steam engine.

The emergence and improvement of the steam engine has promoted the development of social economy, but at the same time, the development of the economy has in turn put forward higher requirements for the steam engine, such as the requirement of high power, high efficiency, light weight and small size. Although many improvements have been made to the steam engine, expanding its range of use and improving its performance, with the development of steam turbines and internal combustion engines, the steam engine has gradually declined due to its insurmountable weaknesses.

1. The steam engine is a reciprocating power machine that converts the energy of steam into mechanical work. The advent of the steam engine led to the Industrial Revolution in the 18th century. Until the beginning of the 20th century, it remained the most important prime mover in the world, and then gradually gave way to internal combustion engines and steam turbines.

2. The steam engine needs a boiler that boils water to produce high-pressure steam, and this boiler can use wood, coal, oil or natural gas or even combustible garbage as a heat source. The steam expansion pushes the piston to do work.