"Heat Engine Efficiency and Environmental Protection" Internal Energy and Heat Engine PPT Courseware

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"Heat Engine Efficiency and Environmental Protection" Internal Energy and Heat Engine PPT Courseware

〖Please tell me〗What are the fuels commonly used in daily life?

Common fuels include coal, petroleum (processed and refined into gasoline, kerosene, diesel and liquefied gas, etc.), natural gas, etc. In rural areas, straw from vegetation and other plants is also used as fuel.

calorific value of fuel

Different fuels of equal mass release different amounts of heat when completely burned.

In physics, the heat released when 1kg of a certain fuel is completely burned is called the calorific value of the fuel.

The calorific value is a physical quantity that reflects the ability of a fuel to convert chemical energy into internal energy when it is burned. The calorific value of the same type of fuel has nothing to do with the quality of the fuel.

The symbol of calorific value: q

Unit: J/kg (J/m3)

The energy released by complete combustion of fuel with mass m is: Q=mq

Q: Heat released by complete combustion of fuel

q: Calorific value of fuel

m: mass of fuel

Heat engine efficiency

Discussion and exchange: When a heat engine is working, can all the chemical energy contained in the fuel be used to do useful work for the outside world?

Discuss

How to improve the efficiency of heat engines?

Make the fuel fully burn;

Minimize various heat losses;

Adopt advanced technology in the design and manufacturing of heat engines;

Pay attention to maintenance to ensure good lubrication and reduce additional energy consumption due to overcoming friction resistance.

think about it

Can a heat engine be 100% efficient? Why?

It cannot reach 100%, because the energy that can be used to do useful work in the heat engine is only a part of the energy released by the complete combustion of the fuel. Because various heat losses are limited by the fuel conditions, this part of the energy is far less than the total energy, so it is different from the fuel. The ratio of the total energy released by complete combustion must be less than 1, that is, the heat engine efficiency is less than 100%.

Dangers of acid rain

1. Direct harm to human health. Sulfuric acid mist and sulfate salt mist are much more toxic than sulfur dioxide and can invade the deep tissues of the lungs, causing pulmonary edema and other diseases that can lead to death.

2. Cause water acidification in rivers and lakes, seriously affecting the growth of aquatic animals and plants.

3. Destroy soil, vegetation and forests.

4. Corrodes metal, paint, leather, textiles and building materials.

5. Penetrate into the ground, making the content of aluminum, copper, zinc, and cadmium in the water many times higher than that in neutral groundwater.

Discussion and exchange

How to protect our environment?

1. Improve combustion equipment and install smoke and dust removal devices;

2. Central heating;

3. Switch to gas fuel and popularize coal gas and natural gas;

4. Fully develop and utilize new energy sources with less pollution and no pollution.

In-person test feedback

1. The average monthly consumption of a family of four using different types of fuel separately is: about 200 kilograms of firewood, about 80 kilograms of bituminous coal, about 30 kilograms of liquefied petroleum gas, and about 60 kilograms of coal gas. Among these four fuels, the one with the highest calorific value is ( )

A. Liquefied petroleum gas B. Coal gas

C. Bituminous coal D. Firewood

2. Rockets in the aerospace industry use liquid hydrogen as fuel. This is because liquid hydrogen has ( )

A. Smaller mass B. Smaller density C. Larger specific heat capacity D. Larger calorific value

3. Diesel engines are commonly used heat engines in industrial and agricultural production. It is known that the efficiency of a certain model of diesel engine is 30%. Complete combustion of 2 kilograms of diesel in the diesel engine can release heat______ J. This heat can be converted by the diesel engine to do useful work for the outside world_ _____J. (The calorific value of diesel is 3.3×107J/kg)

4. How much heat can be released by completely burning 140 grams of coke (the calorific value of coke is 3.0×107J/kg)? If 30% of this heat is absorbed by water, how high can the temperature of 30kg, 20℃ water rise?

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For more information about the PPT courseware "Internal Energy and Heat Engines, Heat Engine Efficiency and Environmental Protection", please click the "Internal Energy and Heat Engines ppt Heat Engine Efficiency and Environmental Protection ppt" tag.

"Heat Engine Efficiency and Environmental Protection" Internal Energy and Heat Engine PPT Courseware 2:

"Heat Engine Efficiency and Environmental Protection" Internal Energy and Heat Engine PPT Courseware 2 1. Calorific value of fuel 1. Definition: People call the energy (heat) released by 1 kg of a certain fuel _______ the calorific value of this fuel. 2. Unit: The _______ symbol is the unit of calorific value of _______ gas fuel..

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Update Time: 2024-08-12

This template belongs to Physics courseware Shanghai Science Edition Ninth Grade Physics industry PPT template

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