What is Adiabatic: Definition and 494 Discussions

In thermodynamics, an adiabatic process (from the Greek adiábatos, meaning “impassable”) is a type of thermodynamic process which occurs without transferring heat or mass between the system and its surroundings. Unlike an isothermal process, an adiabatic process transfers energy to the surroundings only as work. It also conceptually supports the theory used to explain the first law of thermodynamics and is therefore a key thermodynamic concept.
Some chemical and physical processes occur too rapidly for energy to enter or leave the system as heat, allowing a convenient "adiabatic approximation". For example, the adiabatic flame temperature uses this approximation to calculate the upper limit of flame temperature by assuming combustion loses no heat to its surroundings.
In meteorology and oceanography, adiabatic cooling produces condensation of moisture or salinity, oversaturating the parcel. Therefore, the excess must be removed. There, the process becomes a pseudo-adiabatic process whereby the liquid water or salt that condenses is assumed to be removed upon formation by idealized instantaneous precipitation. The pseudoadiabatic process is only defined for expansion because a compressed parcel becomes warmer and remains undersaturated.

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  1. James Ray

    Work done on ideal monatomic gas in adiabatic process

    1. The problem statement, all variables and given/known data Homework Equations [/B] The Attempt at a Solution [/B]
  2. C

    Adiabatic expansion of infinite square well

    Homework Statement Suppose that an infinite square well has width L , 0<x<L. Nowthe right wall expands slowly to 2L. Calculate the geometric phase and the dynamic phase for the wave function at the end of this adiabatic expansion of the well. Note: the expansion of the well does not occur at...
  3. C

    What is the Final Temperature of Methane Gas After Adiabatic Expansion?

    Methane gas at 550K, 5 bar is expanded adiabatically and reversibly to 1 bar. Find the final temperature of the gas. I have made little progress with this... I've calculated the initial volume, and that is all so far. Obviously to find the work usually I'd integrate pressure with respect to...
  4. RoboNerd

    Question on entropy in adiabatic phase change

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  5. grandpa2390

    Find the general expression for the adiabatic relationship

    Homework Statement Find the general expression for the adiabatic relationship between P and V Homework Equations start with ##(\frac{∂P}{∂V})_s## expression for adiabatic relationship between V and T: ##(\frac{∂V}{∂T})_s = \frac{-C_v}{\frac{RT}{V}}## Relationship between S and T...
  6. grandpa2390

    Find the General expression for the adiabatic relationship....

    Homework Statement edit: I figured out my mistake Here's the entire problem. But I don't yet need help with all the steps. I'm getting off on the wrong foot (as usual)a We have shown in class that ideal gas adiabats have the form: ##P_I(V_i)^γ = P_f(V_f)^γ## with the heat capacity ratio: ##γ...
  7. S

    Calculate the change of temperature in terms of T

    Two Thermally insulated cylinders, A and B, of equal volume, both equipped with pistons, are connected by a valve. Initially A has its piston fully withdrawn and contains a perfect monatomic gas at temperature T, while B has its piston fully inserted, and the valve is closed. Calculate the final...
  8. V

    Thermodynamics problem: Gas-filled cylinder & piston SHM oscillator

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  9. John Pang

    B Struggle to understand adiabatic process

    I find really confused about the adiabatic process. According to my textbook, adiabatic process is a process in which no heat is allowed to flow into or out of a system. According to the first law of thermodynamics, change in internal energy=heat added to system- work done by system,so change...
  10. M

    Calculating Internal Energy Change: Path 2 of Carnot Cycle Question

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  11. J

    Pressure inside pneumatic cylinder

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  12. M

    A Why use adiabatic evolution instead of cooling?

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  13. M

    A Computation time for adiabatic evolution

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  14. Jeremy1789

    Adiabatic Process, Internal Energy vs. Enthelpy.

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  15. A

    Reversible vs irreversible work for adiabatic process

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  16. O

    Irreversible adiabatic process - is the entropy change zero?

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  17. grandpa2390

    How much work is done by the Adiabatic Compression of Diatomic Gasses

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  18. grandpa2390

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  19. Raptor112

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  20. AEGIS

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  21. W

    Finding work of adiabatic compressor using ideal gas

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  22. S

    Adiabatic Expansion Pressure Temperature Relation

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  23. Titan97

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  24. Rx7man

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  25. Titan97

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  26. mfig

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  27. vetgirl1990

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  28. K

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  29. H

    The change in entropy in adiabatic process

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  30. J

    Adiabatic expansion of a saturated vapor mix: Δx, ΔS

    Homework Statement A saturated water vapor mix in a 0.05m3 piston-cylinder at 200C with a quality of 0.5 expands adiabatically, producing 500kJ work with a final temperature of 50C. Find: a) final quality b) change in entropy[/B] Homework Equations Q-W=ΔU x=(vavg-vf)/(vg-vf) uavg=uf+xufg...
  31. H

    Question about reversible adiabatic expansion

    Hello guys, I have some troubles to understand a reversible adiabatic expansion. we have dq=0 and dw=-pdV and for a perfect gas dU= Cv*dT. I don't really understand why dU= Cv*dT since we have a variation of volume and it is established that dU= Cv*dT when we haven't any modification of the...
  32. Soumalya

    Adiabatic Saturation Process of Moist Air

    I am facing some overwhelming doubts while trying to study 'Psychrometrics'.Currently I am bamboozled trying to understand the process of adiabatic saturation of moist air. Some of the textbooks claim that a true adiabatic saturation process proceeds along the line of constant enthalpy of moist...
  33. A

    Thermodynamics Problem - Adiabatic Reversible Process....

    Homework Statement A specific type of ideal gas has a specific heat capacity at constant pressure (cp=cv+R) that is a function of temperature T, such that cp=0.5+876T, where cp has units of J/kg/K and T has units of K. The gas, which is initially at T1 = 294 K and P1 = 1x105 Pa, undergoes a...
  34. Pouyan

    Value of gamma in adiabatic process

    In conjunction with diving, a mixture of helium and oxygen called heliox. It will form the background to the following model invoice. Suppose that 1 mole of He and 1 mole of O2 is compressed as fast at half the volume that no heat exchange with the environment have time to take place...
  35. R

    T vs V for adiabatic processes

    Homework Statement [/B] a) Black body radiation: The energy and pressure of black body radiation depend on T and V as E = σV T^4 , p=\frac{1}{3}σT^4 σ = a constant (1) Suppose that the temperature and volume of a box of radiation change adiabatically, which means that there is no...
  36. C

    Relationship Between V and T in Adiabatic Expansion

    Homework Statement The energy and pressure of black body radiation depend on T and V as Eq(1) & Eq(2). Suppose that the temperature and volume of a box of radiation change adiabatically. Find the relation between dE and dT in this process. Next, using Eq(1), show that T ∝V^-1/3 Homework...
  37. A

    Calculating reversible adiabatic expansion

    I have some homework that I am just not able to figure out. There is a 2kg parcel of air at T1=32°C and p1= 0.8 atm This parcel of air expands until it is at T2=12°C Also, during the expansion 3.2 g of water will condense due to the dT (ΔvapH (water) = 40.65kJ mol-1 Also: Cv=0.718 kJ...
  38. J

    Sources to learn about Berry phases and Adiabatic Theorem

    Hello, I recently went through Griffiths' Quantum Mechanics text and there is a chapter called the Adiabatic Theorem that includes Berry phase and the Aharonov-Bohm effect. As I found them very interesting, I would appreciate if anyone could provide me with some good sources(books, internet...
  39. S

    Work Done in Carnot Cycle: Adiabatic Compression

    1.what is the work done in an adiabatic compression process in a carnot cyclewhen we consider work done in efficiency why do we take heat exchange into account i.e.,qs-qrThe Attempt at a Solution
  40. A

    Adiabatic filling of a tank - Minimum work required

    Hi guys, need an help about that problem That's an adiabatic filling of a reservoir (tank) from a line. Line is at 350 K and 8 MPa. The tank is, in the final state, at 365 K and 6 MPa. Tank is insulated (no heat exchanged during the process), and only one stream enter in the tank. How can i...
  41. K

    Piston/bullet inelastic collision (not like other problems)

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  42. steroidjunkie

    Adiabatic equation in dependence on volume and pressure

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  43. S

    Why is the internal energy change of free expansion 0?

    ΔU=q-w and in a free expansion w=0 and Free expansion is an irreversible process in which a gas expands into an insulated evacuated chamber. Does this mean that free expansion is an isolated system? Meaning the walls of the container are adiabatic in which no heat can enter the system and so q=0...
  44. G

    Is an adiabatic process possible for an open system?

    Hello all! I have a hard time about this one: Think of an adiabatic process (can be either reversible or irreversible - doesn't matter). dQ = 0. Assume only, mechanical work is done on/by the system. So by 1st law of thermodynamics, dU =dW. Now, everything is clear to me when I am dealing...
  45. Devang Marvania

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  46. C

    Adiabatic perturbations -- why the name?

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  47. kelvin490

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    From a video lecture, it is mentioned that "dU≠dW in Joule's free expansion if the process is irreversible and adiabatic" Mentioned in around 36:00-38:00 in the video: What I would like to ask is why in this irreversible adiabatic process, dU≠dW? Is it because the W here doesn't include other...
  48. S

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  49. O

    Why does the total temperature not change in adiabatic flow?

    Hi guys, I have a question to you that has been bothering me for a while now. It is about adiabatic flow in a duct or more specifically in the air intake of a jet engine. In lectures and textbooks it is always stated that the total temperature in an adiabatic flow does not change. Hence the...
  50. T

    Relation between adiabatic approximation and imaginary time

    Regarding interacting green's function, I found two different description: 1. usually in QFT: <\Omega|T\{ABC\}|\Omega>=\lim\limits_{T \to \infty(1-i\epsilon)}\frac{<0|T\{A_IB_I U(-T,T)\}|0>}{<0|T\{U(-T,T)\}|0>} 2. usually in quantum many body systems...
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