Spring is coming, what do we touch?

1. Spring is coming, and we have touched (the fragrance of the earth).

2. Spring is coming, and we have touched (the fragrance of flowers).

3. Spring is coming, and we have touched (tender green flower buds).

4. Spring is coming, and we have touched (the willows on the face of the Buddha).

5. Spring is coming, and we have touched (the warm spring breeze).

6. Spring is coming, and we have touched (beautiful butterflies).

Spring is coming, and we can feel the change in temperature, the warmth of the spring breeze, the softness of the earth, and the budding of leaves. You can feel the breath of spring and feel the softness of the earth.

Spring is coming, and we can get in touch with a lot of beautiful scenery, tender flowers and plants, and a very good mood.

The birds are singing and the flowers are fragrant, and the mountains and rivers are beautiful.

Discharge cooling is another type of convection cooling. Unlike regenerative cooling, the coolant used for exhaust cooling absorbs heat to the thrust chamber and is discharged out of the combustion chamber instead of entering the combustion chamber to participate in combustion. Direct drain coolant reduces the thrust chamber specific impulse, so the coolant flow for drain cooling needs to be minimized while only using drain cooling at the outlet section of the nozzle that is relatively less heated.

There is also radiative cooling, in which the heat flow is transferred from the combustion products to the thrust chamber, and then the heat is radiated by the thrust chamber wall to the surrounding space. Radiative cooling is characterized by simplicity and small structural mass. It is mainly used in the extension section of large nozzles and the thrust chamber of small thrust engines using high-temperature resistant materials.

When cooling in the thrust chamber of the tissue, a relatively low temperature liquid or gas protective layer is established on the surface of the thrust chamber wall to reduce the heat flow to the thrust chamber wall, reduce the wall temperature, and achieve cooling. Internal cooling is mainly divided into three methods: internal cooling (shield cooling), membrane cooling and diaphoretic cooling of head tissues. After the internal cooling measures are adopted in the thrust chamber, the mixing ratio near the wall of the combustion chamber is different from the optimal mixing ratio in the central area (in most cases, the near-wall layer rich in fuel is used) due to the need to reduce the temperature of the protective layer, resulting in the uneven distribution of the mixing ratio along the cross-section of the combustion chamber, so that the combustion efficiency is reduced to a certain extent.

Membrane cooling is similar to shield cooling in that it cools the thrust chamber wall by establishing a uniform and stable coolant film or air film protective layer near the inner wall surface, except that the coolant used to establish the protective layer is not injected by the injector, but is supplied through a special cooling belt. The cooling band is generally arranged in a cross-section of the combustion chamber or the convergence section of the nozzle. There can be several cooling bands along the length of the combustion chamber.

In order to improve the stability of the membrane, the coolant often flows through the gaps or small holes in the cooling belts, and when sweating is used, the thrust chamber wall or part of the inner wall is made of porous material with a pore diameter of tens of microns. Porous materials are usually sintered with metal powders or pressed with metal mesh. In this case, the number of pores per unit area is increased by making the micropores in the material as evenly distributed as possible.

The liquid coolant penetrates into the inner wall, creating a protective film that reduces the density of the heat transferred to the wall. When the flow rate of liquid coolant used for sweat cooling is above a certain threshold, a liquid film is formed near the wall of the thrust chamber. When the coolant flow rate is below the critical flow, the inner wall temperature will be higher than the coolant boiling point at the current pressure, and some or all of the coolant will evaporate, forming an air film.

In addition to the above thermal protection, there are other thermal protection methods such as: ablation cooling, thermal insulation cooling, hot melt cooling and composite protection of chamber walls. 3. Thermal protection scheme of high enthalpy gas generator Based on the above methods and the actual situation, the thermal protection method of high enthalpy gas generator is obtained.

The combustion chamber of a high-enthalpy gas generator differs from that of a liquid rocket engine, eliminating the front thrust chamber part, making its structure simpler and more effective. Then, the thermal protection involved is the thermal protection part of the combustion chamber wall. As the fuel enters the combustion chamber, it quickly decomposes and releases large quantities.

Spring is coming, and we are touching the breath of life.

Spring came, we saw the buds on the trees, heard the sound of the water and the birds, smelled the spring rain moistening the earth and the smell of the flowers

Here's an example of fill-in-the-blank:

Spring is coming, and we have touched the temperature of spring.

Spring is coming, and we have touched the breath of spring.

Spring is coming, and we have touched the mild spring breeze.

I saw the spring flowers all over the ground, heard the birds and warblers in spring, smelled the fragrance of the spring garden, and touched the gentle wind and drizzle of spring.

Spring is coming, we debut teacher something.

It's good, it's good, it's big, it's good, it's good,

Spring came, we saw the buds on the trees, heard the sound of the water and the birds, smelled the spring rain moistening the earth and the smell of the flowers

Spring is coming, and we are touching the breath of life.

Spring came, we saw the buds on the trees, heard the sound of the water and the birds, smelled the spring rain moistening the earth and the smell of the flowers

As follows:

1. We touched the warm sun of spring, the cold and delicate rubbing of the spring breeze, the melting of spring snow and the cold after the snow, and the spring flowers blooming one after another.

2. We can touch the spring drizzle, the thawing glacier, and the blooming flowers.

3. We touched the beautiful scene of spring returning to the earth, the recovery of all things, the willow green flowers and red, and the song and swallow dance.

4. When I went out in spring, I touched the fresh air and felt the warm sky, which is particularly desirable, and the flowers are blooming in spring, the grass is green, and the air is also very painstaking, so it is said that spring touches some fresh air.

5. Spring touches hope, it is the expectation of the future, and the reason why people like spring is because it is the beginning of dreams and hope.

1. Spring Heng Sui Tian is coming, and we have touched (the fragrance of the earth).

2. Spring is coming, and we have touched (the fragrance of flowers).

3. Spring came to the stove, and we touched (tender green flower buds).

4. The spring of the Buddha is coming, and we have touched (the willow on the face of the Buddha).

5. Spring is coming, and we have touched (the warm spring breeze).

6. Spring is coming, and we have touched (beautiful butterflies).