What is Compressor: Definition and 199 Discussions

A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids.
Many compressors can be staged, that is, the fluid is compressed several times in steps or stages, to increase discharge pressure. Often, the second stage is physically smaller than the primary stage, to accommodate the already compressed gas without reducing its pressure. Each stage further compresses the gas and increases its pressure and also temperature (if intercooling between stages is not used).

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  1. A

    How do I interpret turbine and compressor maps for optimal selection?

    Hi all, does anyone knows of any good website that teaches you how to read turbine or compressor maps? And possibly teaches you how to select the best turbine / compressor for your particular application? Thank you!
  2. K

    Aftercooler in reciprocating air compressor

    hey guys besides solving the condensation problem what is the purpose of an aftercooler in a reciprocating air compressor??
  3. D

    Is My Compressor Adequate for My Buttler Press Machine?

    Machine and compressor (how to solve this??) Okay all, my first post I am from Australia so not sure which unit you guys preferred in this forum. :smile: Got this project to swap our plant compressor to smaller unit. My compressor details: pressure: 7.5 Bar / 110 psi power: 30 KW / 40...
  4. S

    Sources for Centrifugal Compressor design

    I would like sources for centrifugal compressor design. Anything, such as books, e-books, journals, websites, etc. will do.
  5. S

    Which Compressor Is Best for Achieving 4 Atmospheres: Centrifugal or Axial?

    I have to design a compressor that can compress air from atmosheric pressure to 4 atmosphere, with a mass flow rate of 50898.62 kg/h of compressed air. I am stuck between the choice of two types of compressors. They are: Centrifugal Compressor Axial Compressor I have looked at...
  6. D

    Maximum temperature reached by a reciprocating compressor

    What's the general temperature of reciprocating compressors which are applied in Refrigerators and ACs? It will be good if you give me the temperature of the air which gets compressed...just need a rough idea. Thanks.
  7. P

    Gas compressor vs air compressor

    i recently went to a air compressor workshop. so i want to know what the core differences are in gas compressors and air compressors as the workshop didnt really explain that. cheers
  8. T

    Convert air compressor to air motor?

    Hi I was wondering if a simple 2 stage air compressor can be used as an air motor? And how can I go about transforming it? cheers
  9. A

    Centrifugal Compressor: Converting Kinetic to Pressure Energy

    in the centrifugal compressor the function of the volute or the diffuser to convert kinetic energy into pressure energy my question is isn't it bernouuli equation??and we can apply bernouuli equation to incompressible fluid?? also wouldn't that cause an exapnsion to fluid which causes reduction...
  10. J

    Compressor Simulation: Calculating Outlet Temperature & Mass Flow Rate

    Hallo friends, I am doing simulation of compressor process. I have used the following equation to calculate compressor outlet Temperature and mass flow rate. mass flow rate (m) : flow from compressor map(m3/h)*compressor pressure/(R*Inlet temp*z) T_outlet :T1+ (head*(kappa-1)/...
  11. V

    Power required to drive the compressor

    hi in jet engine power generated for two purpose one is to drive the turbine, compressor and other accosseries Second is for the forward jet thrust take an example A engine generates 15000 lb thrsut. how to calculate the following power and mass flow how much amount of...
  12. M

    How to size motor for compressor

    HI - I'm looking for some help. I'm trying to design a low flow single piston reciprocating compressor. Here is what I have: -Piston bore diameter- 1.50 in -stroke- 0.100" -should be able to go up to 30 psig average pressure will be 20psig -I am looking for the air flow to be 4.00 lpm...
  13. W

    Compressor vs Condenser - what's the difference?

    I read about refrigerators and often a fridge has two components: 1. compressor 2. condenser The compressor compresses the vapor - what does it actually do? does it increase the temperature of the vapor? The condenser condenses the vapor into liquid and then the liquid is expanded...
  14. N

    Thermodynamics Question (Centrifugal Compressor)

    Hi there guys, Sorryto make my first post on here a request, but i am a little puzzled at the moment by this latest question I have been set! My lecture notes do not seem to cover this in any detail at all, and resources on the internet are either avoiding me or i am just plain blind! 1...
  15. M

    Cost of Compressors for 9.36 kW, 59 kg/h Methane

    I need to know the cost of a compressor that can be used to compress 59 kg/h methane from 1 atm to 25 atm. The work required by the compressor is 9.36 kW. Any idea where i can find the cost of compressors?
  16. D

    Minimization of losses in a piston compressor

    Hello. I need to minimize all types of manageable losses (mechanical and thermodynamic) in a reciprocating compressor. Does anyone have more suggestions besides having a high efficiency motor, no loss tank drain and high efficiency dual controller?
  17. S

    Designing a Turbine and Compressor: Challenges and Considerations

    i am doing a project which involves me designing a turbine and compressor based on the turbocharger principles. i was wondering if anyone knew of an easy way to carry this out. any help would be excellent!
  18. R

    A multipurpose compressor possible ?

    i m curious . Can an AIR compressor be used to pump water? for arguments sake just a simple for reciprocating compressor. i mean how different can it be? one fluid is replaced with another right !
  19. 2

    Determine the sound power level of the compressor

    A compressor installed in a large factory radiates sound uniformly. its sound pressure level at 45m away is measured as 68dB. Determine (a) the sound power level of the compressor (b) the power output of the [B]compressor
  20. T

    Compressor exit Temperature.

    Product Compression. I am currently doing some work on compression. I know the flowrate in and the pressure and temperature in, and I know the pressure (and flowrate) out. Can I determine the temperature out? I have tried using P1V1/T1=P2V2/T2, but as V is a function of T (using values from...
  21. G

    Internal/external energy in compressor

    This is about how to relate an abstraction of thermodynamics to a real compressor. The difference of the specific heats is called "external work" since in the legendary cylinder holding a pound of air being heated one degree, the spec heat capacity at constant pressure is this much more than...
  22. Saladsamurai

    Why do Jet Engines Have a Compressor?

    So like it says. It may be a silly question, but I am doing some reading on jet engines (on Wiki) and I am having trouble finding an explanation as to why we want to increase the pressure of the air before it goes into combustion. Does this just another way of increasing the thrust? Thanks...
  23. M

    Rotary Vane Compressor Design Calculations

    I am designing a sliding vane rotary compressor for a supercharger application on a small horsepower engine, but I am having trouble with the calculations. I have some estimations that I would hope to be correct (or close) but have no way to verify them at this point. One of the toughest parts...
  24. T

    Thermodynamic Compressor Question

    Homework Statement If there's a polytropic process (n = 1.51) compressor that compresses air (Ideal Gas) as: In: 100 kPa @ 25c Out: 30 MPa Given Data: Mass (m) = 105 kg, Work done by compressor (W) = 160000 kJ a. What is the exit temperature of the air from the compressor? b. If an...
  25. R

    Rotary air compressor and vortex tubes questions?

    Hello, below are some specs I was provided of a micro screw air compressor, its physical dimensions are 4x4x4 and it seems pretty impressive for its size. However I am trying to understand a few things about the data that was provided. I am provided 6 charts on power/airflow/psi etc, each...
  26. A

    Calculating Probability of Subsea Compressor System Failure

    [SOLVED] Bolean Algebra Question The failure of a subsea compressor system is described by the following Boolean Algebra statement: F = A UBU(CUD) If P[A] = 0.01; P[B] = 0.0034; P[C] = 0.00067; P[D] = 0.002, calculate the probability P[F] given independence between A,B,C,D...
  27. A

    Rotary Vane Compressor Question

    Im quite new to this and having trouble in understanding the topic. - Rotary Vane Compressor. Can someone please explain why the air mass flow rate reduces when the delivery pressure increases? Thanks
  28. B

    Air Compressor Motor Selection & RPM Guide

    If I have an air compessor that uses an 11 horse power gas engine. How do I know what size electric motor, and what RPM will do the same job?
  29. R

    Can a 5HP Electric Motor Replace a 10HP Compressor?

    I have a 10 HP electric motor on a compressor. The motor goes south but I have a good 5 HP electric motor. Will it work? I am sure I could not get the PSI that the 10 horse produced, probably have to reduced the hi shutoff. tks
  30. A

    Why Are Compressor Tanks & Gas Containers Round?

    Dear all I need theoretical backround regarding shape of the compressor tanks or tanker lorries as well as gas carrying containers . Why such are round shape instead of rectangle or square? Any papers ,references sites are welcome Thanks Prakash
  31. A

    How we increase the pressure of a air compressor

    my question is that.. is there any way to increase the pressure from 25 psi to 125 psi...is the volume is 5.2m3/min...
  32. S

    Compressor Power Equation | Factors & Link

    Please give me the equation with a link if possible for determining power for a compressor. I know volume x pressure differential / efficiency but I think the gas being compressed also is a factor. Thank you.
  33. P

    How does a jet-engine compressor compress air?

    ? please help me out folks pleasezzzzzzzzzzzzzzzzz
  34. B

    Help about reliability of a compressor

    hi, can someone tell me what environmental conditions affect the output and reliability of the compressor components ?? thanks barbo
  35. J

    Thermodynamics compressor Question

    Homework Statement Air enters a compressor operating at a steady state with a pressure of 14.7 psi, a temperature of 70 F , and a volumetric flow rate of 500 ft^3/min. The air velocity in the exit pipe is 700ft/s and the exit pressure is 120 psi. If each unit mass of air passing from the...
  36. O

    Can a Car Airconditioning Compressor be Used as a Pico Steam Turbine?

    Hi All, I am a solar thermal enthusiast seeking to try out a few things. I need some info on using car aircondition compressor as a pico steam turbine if it is possible. Links, suggestions and opinions are welcome. Regards, Solomon.
  37. N

    'Jet' engine with positive displacement compressor?

    Aside from early diesel engines, does anyone know of brayton-cycle engine that uses a positive displacement compressor rather than an aerodynamic one?
  38. S

    Analysis of Performance of Rotary Vane Compressor

    Hello all. I have the following questions regarding the analysis of the performance of a rotary vane compressor. 1) Why can the specific kinetic and potential energy changes normally be neglected? 2) If an adiabatic compression is considered, what is the primary cause of energy loss...
  39. L

    Can a Normal Refrigerator Compressor Pump Liquids for a DIY Heat Engine?

    I need to pump a refrigerant in its liquid state (from low to high pressure), and I am wondering if a normal rerfrigerator compressor is capable of doing this. I don't know the internal specifics; if it somehow depends on the compressability of the fluid it's pumping. I would prefer to use one...
  40. S

    Rotary vane compressor lost motion?

    In a rotary vane compressor, the vanes constantly move in and out. Does the work required to accelerate the vanes radially outward and then inward cancel out or is the kinetic energy of the vanes lost and completely converted to heat?
  41. Q_Goest

    Selecting an Oil for High Pressure Hydrogen Compressor

    I'm in the process of designing a high pressure hydrogen compressor. In this machine, an oil will be in direct contact with the hydrogen. To minimize the amount of oil vapor that enters the hydrogen and must be separated, an oil with high molecular weight and low vapor pressure should be best...
  42. S

    Calculating Annulus Area in a Compressor

    What is annulus area in a compressor?
  43. S

    Effect of high temp. compressor

    If the compressor in a turbojet is at high temperatures, it will heat up the air while compressing it. Does it have a negative effect on propulsion? If so, then is it because it reduces the efficiency of the burner as well as hampers the intake of air by increasing its pressure delivering...
  44. S

    What Oil to Use for a Nikota Air Compressor?

    I just have purchased an air compressor Nikota 2 hp., 4 gallon twin tank, 115 psi, and i was wondering what kind of oil i am supposed to put in the pump also i don't have any directions any suggestions? thanks
  45. I

    How Does Size Affect Air Compressor Performance?

    i have a couple questions about air compressors.. 1) how dependant is psi/cfm on size? and can this barrier be overcome by a greater input force/speed? 2) which is reliant on speed the compressor is turning, flow rate or pressure?
  46. S

    Air Compressor Schematics & Homebuilt Projects

    Does anyone know of any sites that have a good schematic of an air compressor? or possibly some sites about homebuilt air compressors? thanks
  47. W

    Cooling capacity of an aircon compressor

    how does the cooling capacity of an aircon compressor exceed that of the power supplied to it? from what i understand, energy cannot be created or destroyed. so when we put in 500W of electrical energy into a compressor, why do we expect the cooling capacity to be 1500W. does that mean that...
  48. D

    1.5 HP compressor on a 400 W inverter

    i have a 1.5 HP air compressor and a 400 W DC to AC inverter. i was wondering if i use this in my car what will happen. 1.5 HP is obviously close to 3 times more power than the inverter can supply. i would obviously keep my car running to keep the altnernator charging the battery. would the...
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