Adiabatic Definition and 498 Threads

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.

View More On Wikipedia.org
Recent contents Top users
  1. K

    I Pressurization rate vs. Mass Flow rate

    Good afternoon all, I am doing some back of napkin calcs for work and am having trouble finding an answer (or one that I can understand--its been a while since undergrad). We have a valve that has particular flow rate requirements to prevent unseating the valve seal. This is a mass flow rate...
  2. S

    Work in a process which is both adiabatic and isobaric?

    In a adiabatic process (not necessarily reversible) from ##V_a## to ##V_b## the work can be written as $$W=\frac{p_aV_a-p_bV_b}{\gamma-1}$$ Where ##\gamma= \frac{c_p}{c_v}## Suppose that the adiabatic process in question (again, not necessarily reversible, so ##pV^{\gamma}## can also not be...
  3. Dr. Who

    I Relation between 'P' and 'V' for an Adiabatic process

    Hi All, I have a little query concerning the derivation of PV γ = constant. In my textbook of Physics, first they give the equation for adiabatic process using the first law of Thermodynamics, as; dEint = W → (1) where, ΔEint ⇒ change in internal energy and W ⇒ workdone Then, they used...
  4. S

    Difference between Isothermal and Adiabatic?

    So for Isothermal, there is no change of T so hence delta U is 0. However, if there isn't a change of temperature, how is there a change of Q? I thought heat was the flow of energy of different temperatures. This confuses me for adiabatic as well. With no heat, how is there a temperature change...
  5. 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]
  6. 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...
  7. 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...
  8. RoboNerd

    Question on entropy in adiabatic phase change

    Homework Statement Consider a closed, adiabatic system consisting of a mixture of liquid and solid substance Z at equilibrium at its melting point. Z (solid) <---------> Z (liquid) Which of the following statements is true regarding the system? A) The entropy of the system is at a maximum...
  9. 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...
  10. 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...
  11. 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...
  12. V

    Thermodynamics problem: Gas-filled cylinder & piston SHM oscillator

    Homework Statement An ideal gas enclosed in a vertical cylindrical container supports a freely moving piston of mass M. The piston and cylinder have equal cross sectional area A. When the piston is in equilibrium, the volume of the gas is V0 and its pressure is P0. The piston is slightly...
  13. 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...
  14. M

    Calculating Internal Energy Change: Path 2 of Carnot Cycle Question

    Homework Statement A gas is to be expanded from initial stage i to final stage f along either path 1 or path 2 on a p-V diagram. Path 1 consists of three steps: an isothermal expansion(work is 23J in magnitude), an adiabatic expansion(work is 35J in magnitude), and another isothermal expansion...
  15. J

    Pressure inside pneumatic cylinder

    Hello, I'm having issues with pressure calculations that I'm using for a double acting pneumatic cylinder. In my application, I start the piston near one end of the cylinder with both sides closed, and then move the piston towards the other end. At each point, I update the pressure, volume, and...
  16. M

    A Why use adiabatic evolution instead of cooling?

    Hi everyone, For adibatic quantum computation one prepares the groundstate of a particular Hamiltonian and than adiabatically evolves the system to a problem Hamiltonian Hp which groundstate encodes the desired solution to a satisfiability problem. If the evolution takes place slowly the system...
  17. M

    A Computation time for adiabatic evolution

    Hi, my problem: following the adiabatic theorem we get an equation for the coefficients: \dot{a}_{m}=-a_{m} \langle{\psi_{m}} | \dot{\psi}_{m}\rangle - \sum_{n \neq m} \frac{\langle \psi_{m} | \dot{H}| \psi_{m}\rangle}{E_{n}-E_{m}} exp(\int_ 0^t E_{n}(t')-E_{m}(t') \, dt') we start in an...
  18. Jeremy1789

    Adiabatic Process, Internal Energy vs. Enthelpy.

    I'm struggling to understand a concept which I assume is basic, but I can't seem to fit the pieces together. When speaking about an ideal gas, I understand that ΔH = ΔU + Δ(PV) = ΔU + RΔT So far so good. I also understand the relationship: ΔU = Q + W... (W here is work being done on the...
  19. A

    Reversible vs irreversible work for adiabatic process

    I have a gas transitioning adiabatically between A (P1, V1) and B (P2, V2) where P1>P2 and V2>V1. The question is to determine the net work done on the gas if the gas is first expanded reversibly from A to B (w = dE = Cv(T2-T1)), and then compressed irreversibly from B to A (w = -Pext(V1-V2)) at...
  20. O

    Irreversible adiabatic process - is the entropy change zero?

    Homework Statement A well insulated container consists of two equal volumes separated by a partition - one half an ideal gas while the other is a vacuum. The partition is removed, and the gas expands. What is the entropy change per mole? Homework Equations dS = dQrev/T S/R = Cp/R dT/T -...
  21. grandpa2390

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

    I apologize if my questions were in the wrong place. I am in "Advanced" Physics Classes. And so I post the questions from those classes in the Advanced Physics forum. And these are questions that weren't covered in Introductory Physics (1st three semesters). But they keep being moved to this...
  22. grandpa2390

    What is the volume of the gas after adiabatic compression

    Homework Statement 1 liter of ideal diatomic gas (allow for rotation but not vibration) at a pressure of 1 atmosphere and a temperature of 300 K is compressed adiabatically to a pressure of 7 atm. What is the volume of the gas after compression? Homework Equations PV=NKT PV=nRT ##U_T##=f/2*NKT...
  23. Raptor112

    Are Adiabatic Invariants Violated for 10 keV Electrons During a Substorm?

    Homework Statement Consider the following disturbances. Clearly state for 10 keV electrons if any of the three adiabatic invariants violated, and justify your answer? (i) The magnetic field at L = 6.5 (~geo-stationary orbit) steadily changes strength and direction from one state to another in a...
  24. AEGIS

    Adiabatic or Isothermal? Compressed air energy storage

    Hi, I'm doing a high school physics project and am trying to figure out if a certain setup that I'm using is adiabatic or isothermal, in order to determine what equation I can use to calculate the work that my setup does-- the threads I've come across so far only explain the difference, but not...
  25. W

    Finding work of adiabatic compressor using ideal gas

    Homework Statement Methane at ## P_1 ## and ## T_1 ## is compressed to a pressure of ## P_2 ## adiabatically at steady-state. Calculate the work done on the compressor and the temperature ## T_2 ## of the discharge gas. Use ideal gas model. Given: ## T_1, P_1, P_2, C_p, \gamma = 1.4 ## ##...
  26. S

    Adiabatic Expansion Pressure Temperature Relation

    Homework Statement The problem is in the context of convection in the troposphere Show that when an ideal gas expands adiabatically, the temperature and pressure are related by the differential equation \frac{dT}{dP} = \frac{2}{f+2} \frac{T}{P} Homework Equations Ideal gas law PV = nRT...
  27. Titan97

    Thermodynamics problem involving adiabatic vessels

    Homework Statement Two adiabatic vessels containing ##n## moles of mono atomic and diatomic gas respectively are connected by a rod of length ##l##, cross sectional area ##A## and thermal conductivity ##k##. The surface of the rod is insulated. The initial temperatures of the vessels are...
  28. Rx7man

    Centrifugal compressors, adiabatic compression

    Homework Statement I am working on creating a spreadsheet where you can input the parameters of an engine at a given rotational speed such as volumetric efficiency, boost pressure, atmospheric pressure and temperature, and compressor efficiency... It's been a very long time since I've done...
  29. Titan97

    Find the change in temperature during adiabatic compression

    Homework Statement Homework Equations $$PV^{\gamma}=\mathrm{constant}$$ The Attempt at a Solution Initially, the piston will get a velocity ##v##. But the chamber will move too because of the forces exerted by the gas. Since total external force is zero, velocity of centre of mass is...
  30. mfig

    I Why do we see the claim that an isentropic process is adiabatic and reversible?

    Why do we always see the claim that an isentropic process for a system is adiabatic and reversible? The change in entropy for a process is the sum of the entropy transfer accompanying heat and the entropy production. The entropy production term is always at least zero, and the transfer term...
  31. vetgirl1990

    Adiabatic Expansion of a Gas: Final Pressure-Volume Product Calculation

    Homework Statement A gas consisting of diatomic molecules that can rotate but not oscillate at a given range of temperatures expands adiabatically from pressure of 365Pa and volume of 70m3, doing 101J of work, while expanding to a final volume. What is its final PV (pressure volume) product...
  32. K

    Ideal gas volume work expression (adiabatic)

    Homework Statement I have the following task: Homework EquationsThe Attempt at a Solution But I don't understand how to solve it. Can somebody help me?[/B]
  33. H

    The change in entropy in adiabatic process

    Hello everyone, I still wonder if there's a change in entropy in adiabatic process. The definition of entropy is a quantity represents for the disorder state of a system. Arccording to kinetic theory of gas, temperature is for the state of chaotic motion of molecules. So I'm very confuse, can...
  34. 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...
  35. 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...
  36. 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...
  37. 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...
  38. 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...
  39. R

    How Do T and V Relate in Adiabatic Processes for Different Substances?

    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...
  40. 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...
  41. 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...
  42. 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...
  43. 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
  44. 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...
  45. K

    Piston/bullet inelastic collision (not like other problems)

    Homework Statement a bullet has mass=0.01kg velocity=150m/s, you have a cylinder with 5.0m^3 of air at STP with a piston at one end that has mass=0.1kg and surface area of 10cm^3 and is at rest. The bullet strikes and embeds itself into the piston. The system is to be considered adiabatic after...
  46. steroidjunkie

    Adiabatic equation in dependence on volume and pressure

    Homework Statement Find: (a) Equation of state $$f (p, V, T)$$ and (b) Adiabatic equation in dependence on volume and pressure. Internal energy $$U(V, S)=\frac{1}{aV} ln(\frac{S}{\gamma})$$ where a and ##\gamma## are positive constants. Homework Equations (a) ##dU=TdS-pdV \rightarrow##...
  47. 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...
  48. 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...
  49. Devang Marvania

    Mixing of two air flow at different pressure

    Hi Friends! Here is my query : I have two source of air supply with different pressures, temperatures and with different mass flow rates. Input 1: P1,T1,m1. Input 2:P2,T2,m2. Output: P3,T3,m3. P,T and m refers to pressure, temperature and mass flow rate respectively. If the mixing is being done...
  50. C

    Adiabatic perturbations -- why the name?

    In cosmological perturbation theory one can make an argument that very early on the relation between dark-matter perturbations and photon-temperature perturbations satisfies $$\delta = 3\Theta_0 + \text{constant}.$$ If ##\text{constant} = 0## we call these primordial perturbations adiabatic and...
Back
Top