What is polytropic expansion?

What is polytropic expansion?

A polytropic process is a thermodynamic process that obeys the relation: where p is the pressure, V is volume, n is the polytropic index, and C is a constant. The polytropic process equation can describe multiple expansion and compression processes which include heat transfer.

How do you calculate gas expansion?

Pressure-volume work

1. Work is the energy required to move something against a force.
2. The energy of a system can change due to work and other forms of energy transfer such as heat.
3. Gases do expansion or compression work following the equation: work = − P Δ V \text {work} = -\text P\Delta \text V work=−PΔV.

Is isothermal expansion a polytropic process?

Polytropic Compression/Expansion Process An ideal isothermal process must occur very slowly to keep the gas temperature constant. In practice most expansion and compression processes are somewhere in between, or said to be polytropic.

What is meant by polytropic gas?

The term “polytropic” was originally coined to describe any reversible process on any open or closed system of gas or vapor which involves both heat and work transfer, such that a specified combination of properties were maintained constant throughout the process.

What is gas expansion meaning?

1. An increase in size, volume, or quantity, usually due to heating. When substances are heated, the molecular bonds between their particles are weakened, and the particles move faster, causing the substance to expand.

What is gas expansion?

Gas expansion is the discomfort caused by the expansion of air in the body cavities due to certain factors. The gas expansion puts pressure on the stomach and intestines, causing pain.

What happens when a gas expands?

As a gas (like air) expands, the value of V increases and this has the effect of increasing T (The temperature). As the energy needed to increase it’s temperature must be supplied from somewhere, the gas takes the energy from the surrounding system giving the effect of cooling.

Why is Polytropic process called polytropic?

What is Polytropic process example?

the case < n < ∞, in this process heat and work flows go in the same direction, This process occurs, for example, in an internal combustion engine (e.g. Otto cycle), in which there are heat loses through the cylinder walls during gas expansion (power stroke).

What is compression index in soil mechanics?

Compression index describes variation of void ratio as a function of the change of effective stress plotted in the logarithmic scale. It therefore represents deformative characteristics of overconsolidated soil. Typical range of compression index is 0.1 to 10.

What is polytropic compression and expansion process?

Polytropic Compression/Expansion Process An ideal isothermal process must occur very slowly to keep the gas temperature constant. An ideal adiabatic process must occur very rapidly without any flow of energy in or out of the system. In practice most expansion and compression processes are somewhere in between, or said to be polytropic.

What is polytropic process of an ideal gas?

Polytropic Process of an Ideal Gas •The relationship between the pressure and volume during compression or expansion of an ideal gas can be described analytically. One form of this relationship is given by the equation pVn = constant •where n is a constant for the particular process.

How do you find the constant of a polytropic process?

One form of this relationship is given by the equation pVn = constant. • where n is a constant for the particular process. • A thermodynamic process described by the above equation is called a Polytropic process. • For a Polytropic process between two states 1-2 p V p Vn constant 2 2 n 1 1 = =.

What is isentropic compression and expansion?

Isentropic (or adiabatic) Compression/Expansion Processes. If compression or expansion of gas takes place with no flow of heat energy either into or out of the gas – the process is said to be isentropic or adiabatic.