Why don't you just read your book, instead of having other people answer you homework for you.
Since the question is about heat exchange, I assume it is a man made. The first form of heat exchange is cooking. The first fluid is then water.
Convection
Convection
C. Convection
Efficiency of a space engine is the ratio of power to weight / and power to thrust ratio , used in duct propulsion by conversion of heat energy into exhaust velocity. Space engines are thermo acoustic engines that use bi propellant or solid fuel. Engines use different heat conversion methods in chemical or electrical power to ionize atoms and create voltage gradient to accelerate the ions to high exhaust velocity. The high temperature in the Venus atmosphere 7530Kelvin/4600 C is the main cause of inefficiency in space engine that can only use only heat exhaust for propulsion. The other reasons for inefficiency of a heat propulsion engine is the dominant 96% CO2 + 4% Nitrogen with clouds of sulfuric acid in the atmosphere.
Slow speed propulsion engines, such as diesel engines used in ships, have high thermal efficiency due to their large size and design. The large size allows for better combustion, reduced heat losses, and increased efficiency in converting fuel energy into mechanical work. Additionally, slow speed engines operate at a lower compression ratio, which helps improve thermal efficiency by reducing heat losses during combustion.
The transfer of heat in a cycle through a fluid is known as thermodynamic heat transfer. During this process, heat is transferred from a high-temperature reservoir to the fluid, which then carries this heat to the low-temperature reservoir, completing the cycle. This phenomenon is commonly seen in various engineering systems like refrigerators, heat engines, and air conditioning units.
Heat energy is used for a variety of purposes, such as cooking food, heating buildings, generating electricity in power plants, and in industrial processes like manufacturing and chemical reactions. It is also used in transportation, such as in engines and propulsion systems.
Many things use a flame, such as stoves for cooking, furnaces for heating, candles for illumination, and engines for propulsion. Flames are a common source of heat and light energy in various applications.
Steam engines are used in modern industries and applications today primarily for power generation and propulsion. They are commonly found in power plants, locomotives, and certain types of ships. Steam engines convert heat energy into mechanical energy, making them efficient for tasks that require a high level of power output.
engines get discolored because of the heat . the heat comes from combustion from gass and air
Because they convert heat to mechanical energy. In both cases they harnes the heat produced as fuel combusts and convert it to pressureized fluid. That fluid then either pushes a piston or pushes on turbine blades and spins a shaft creating usable mechanical energy. The only difference is where the combustion takes place, inside the engine (gasoline and diesel powere piston and turbines) or externally (wood, coal or other fuel powered steam turbines). Most fuels could be used for both internal and external combustion engines, the difference is if the fuel ever enters the engine itself or if only the steam or other working fluid enters the engine.
by engine
Yes. Gasoline and diesel engines are both heat engines.
Yes, exothermic reactions are commonly used to power engines, such as in combustion engines where fuel undergoes exothermic reactions to generate heat and drive the pistons. This process is used in vehicles like cars and airplanes to provide propulsion.
Yes. Heat engines come in various forms. For example, internal combustion using gasoline or diesel, external combustion (not much used), steam engines reciprocating or turbine, gas turbines, rocket engines.
Heat engines convert chemical energy into thermal energy through combustion of fuel. The thermal energy causes a fluid (like water or air) to expand and create pressure, which is then used to drive a turbine or piston. The mechanical energy generated from the expansion of the fluid is then transformed into kinetic energy to produce motion or do work.