Compressor Definition and 186 Threads

Hello all, I am new to thermodynamics applied to turbines and compressors and I am trying to get my head around what is represented when calculating the work of a compression/expansion process using the polytropic exponent as oppose to the specific heat ratio of 1.4 (I'm working with air). The...

Dear all, I would like to have your help for a problem that i face. I know that it is a little bit ridiculous, but my brain is stacked right now! I have a helium compressor that i want to fill it with helium at room temperature 293K @ 1.013bar. This compressor will be connected with a pipe. As...

Hi I have uploaded centrifugal compressor performance curve. I want to know how Mass Flow vs Pressure Ratio curve plotted under different efficiency since efficiency is a constant for a compressor. Please help.

How can i calculate the water temperatur in step 3? Do i need more information? We can assume the water temperatur in step 2 is anything between 288 and 313K. If anyone knows how to calculate step 4, ill take that as well.

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 ## ##...

Homework Statement Air is drawn into a compressor at normal temperature and pressure (N.T.P.) and compressed to a pressure of 6 bar gauge. After compression the air is delivered at 1.2m3 min–1 and cooled to a temperature of 30°C, at which point condensate is collected at the rate of 2 litres...

hi guys... am working on a variable refrigerant flow (VRF) type air conditioner. my aim is to change the capacity of the compressor based on load change. i can vary compressor capacity by using inverter...now my doubt is on what basis i should change compressor speed for muti evaporator...

Hi all, Is there a correlation between an Air Dryer capacity and the exhaust pipe diameter? How would a small exhaust pipe diameter (not able to exhaust air enough) affects the capacity of an air dryer? If it does, could you expand on this? Thank you

Homework Statement Nitrogen enters an insulated compressor operating at steady state at 1 bar, 310 K with a mass flow rate of 1000 kg/h and exits at 10 bar. Change in KE and PE is zero. Heat transfer is zero. Assume ideal gas with k=1.391. Find minimum theoretical power input required and the...

I'm working on a project to design Atmospheric Water Generator, to generate 3 litres of water per day. and I'm using the same concept as dehumidifier. My problem is I want to figure out how powerful my compressor should be. I need to calculate that, given a heat flow rate of 352.91 kJ/hour...

Hello everyone. I'm working those days on my graduation project, and I need a little assistance. I have to choose a compressor that would be driven by diesel engine. The compressor should supply about 1.7 kg air and compress it to 2 atmospheres. It seems that centrifugal compressor or axial may...

why do we use Cp value while finding work of the compressor or the expander i.e W=CpdT=H2-H1 H= enthalpy when we know pressure inside the expander or compressor drops it basically is isentropic process why not we use isentropic work eqn

Hi Everyone, So I seem to have many problems understanding the Psychrometric chart and its physical meaning. First of all, I would be so thankful if you could introduce me a source which can be useful to physically and fundamentally understand the dew point, effect of pressure, humidity... and...

Hello everyone, i am currently dimensioning a compression system using a vehicle turbocharger and need to find a way to relate the pressure ratio of the compressor and the mass flow rate. (flows trough compressor and turbine are of course separated) For the turbine, one can use Stodola's...

Hi All, Is there a list of thermodynamics equations regarding the chiller process from condenser, evaporator, compressor to the regulator. Say I have chiller load at 90%, what set of equations could I use to determine the supply temperature of chill water and condenser supply temperature to...

Homework Statement Air enters a compressor at 100kPa and 20 oC in steady flow rate . Air is compressed to 1 Mpa. The heat loss is 10% of the power of the compressor . Air enters with speed of 50m/s in a surface of 0,009 m2 and leaves with speed 120 m/s from a surface of 0,0005 m2. Find the...

I would like to clear out my understanding of gas compressor. If it is moving at constant RPM, is it mean that it can only allow same volumetric flow rate all the time? So the power will remain constant too, (P=VI) then voltage and current will varies. My investigation is to find why there is...

Hi, I am currently trying to model a water-cooled scroll compressor but do not have enough data to predict output conditions. At the moment, I can collect inlet and discharge pressure, outlet temperature, water mass flow rate as well as inlet and outlet temperature. I would like to be able to...

Homework Statement [/B] Thermodynamics problem Air enters a compressor at a temperature of 290 Kelvin and pressure 100 kPa with a stable volume flow of 2.5 m^3/s. The output temperature of the compressor is is 400 Kelvin and the velocity of the flow is 30 m/s. Air is implied to be an ideal gas...

I reference this forum all the time and you guys are always good at breaking down confusing questions so I decided I needed to make an account and get some help with a mental struggle I have been having for quite some time! Two commonly discussed ways of improving a compressor's efficiency in a...

I posted this on Eng-tips and no replies yet:( I'm trying to design an as-simple-and-cheap-as-possible supersonic wind tunnel using an air compressor (this even possible? given the energy losses from shock waves...). I have access to a Porter-Cable 150psi, .8hp air compressor. Questions: 1...

Hi everyone, I need to do a presentation to a high school class about the physics behind a turbocharger and was looking for some help getting which principals/laws explain what happens when a turbocharger is used within a car i.e.; Thermodynamics, gas laws. I just need a direction in which...

Hello, I've got one problem with fluid flow reaction force which acts on compressor. I hope you can help me with that. Here is a sketch to my question: I wonder in which direction resultant force will be directed. I understand that air is flowing from left to right with inlet velocity V1...

I want to know what is compressor blade loading. When it is said that a compressor blade will be overloaded near the hub, what does it means?

Hi! For our class project, we have to design a system that freezes an amount of water as quick as possible. The refrigerant is R134a. The compressor is known. I don't really know how to get started here. How do I choose the evaporator pressure and the superheating, and equally the condensor...

Homework Statement The prompt says that there's a 2-stage adiabatic compression cycle where the first compressor pressurizes atmospheric air (0psig or 14.7psia) to P2, and the compressed air is cooled by a cooler to the initial temperature, and passes through another compressor to 350psig or...

Homework Statement The pressure ratio of an air standard gas-turbine cycle is 8/1 and the inlet conditions to the compressor are 200 KPa and 30C. The turbine is limited to a temperature of 1500K and the compressor and turbine adiabatic efficiencies are 60 and 90 respectively. Calculate...

Hy please help me .i am strugling to calculate the mechanical efficiency of a compressor as i am not given power output and power output

Hi, I want to use a compressor aftercooler and to size it I tried to calculate the heat load needed for lowering the outlet Tª to about 50ºC. I was checking the heat load of compressed air at 7bar 100L/min, the compressor manufacturer says outlet Tª should be about 150ºC. Input electrical...

I understand that you need certain work for the refrigerator to work, and that it comes from the compressor. Why isn't a pump used instead? Why do you have to compress and heat the air so much? Thank you

Very new to these matters, so please bear with me if my basic HVAC understanding is imprecise: To start, I had a system in which airflow through a pipe was A) filtered for contaminants before flowing on to B) a compressor which outputted the flow at an increased discharge pressure. The A)...

Hi all, Currently I am undertaking a project and I am a little bit confused about the free air delivery (F.A.D.) of an air compressor because I need to purchase an air flow meter and don't want to buy something completely out of the ball park. From the information sheet, the compressor has...

I was revising for my course exam and encountered a question in my book (Applied Thermodynamics for Engineering Technologists, p 66 example 3.3) which stated that a compressor follows a polytropic process to compress air; I understood the calculation process which resulted in heat being...

Hi, I went through many resources but I am not able to understand as to what stall/surge means for an axial compressor means. I am not able to imagine or correlate it. I want to physically understand what happens in a compressor when it is stalled. For eg: Can a ceiling fan stall when the angle...

Compressor wanted -- produce up to 100 bar/1450 psi @ 40Vdc I'm searching for a compressor that is compact but is able to produce up to 100 bar/1450 psi. It also should work on max 40V DC. Please say if you know similar compressors! Thanx already :)

Suppose the 2 passengers in my car generate 1000W of heat and the sunlight falling inside the car generates 1000W of heat, how much heat should my compressor add on the refrigerant to suck away all the 2000W of heat in the car? I realize that a compressor is rated in pressure but I would like...

Relativistic compressor "paradox" Let's say we have a metro tunnel that is a circular loop with 1 m x 1 m rectangular cross section. The tunnel is 100 m long. There's a 50 m long train in the tunnel, the train fits snuggly in the tunnel. And there's air in the tunnel, at 1 atm pressure, and...

Hello, When using a multistage compressor that is assumed to be isentropic with no interstage temperature increases, is it assumed each stage does the same amount of power?

Homework Statement A chlorinator operates at twice the pressure of the Cl2 recovery stream. To recycle the Cl2, it has to be compressed. Whats the minimium energy consumption of the compressor (per mol of Cl2) if it leaves the recovery stream at 100 Degrees. Assume isentropic and Q = 0 Cp =...

Homework Statement A small adiabatic air compressor is used to pump air into a 20-m3 insulated tank. The tank initially contains air at 25°C and 101.33 kPa, exactly the conditions at which air enters the compressor. The pumping process continues until the pressure in the tank reaches 1,000...

Homework Statement Nitrogen was compressed from initial pressure of 101 kPa to a higher pressure. The respective enthalpies are: 54 kJ/kg and 350 kJ/kg. The compression process is adiabatic and ideal. The volume flow rate is 0.05 m^3/s. Density of Nitrogen before entering the compressor is...

I've been lurking on these forums for years now; so much of my idea-seeking brings me here, it's remarkable, even to me, that I've never created an account. Here I am now though, so let's jump in shall we? Background: I'm designing an off-grid house for myself. I have most of the details...

Hello to everyone that reads this, I have to replace an old compressor with a new one. The trick is that i need to calculate the everything about the new one before i put it in. So i can convince everyone that it's a smart choice. The vapor compression cycle will remain the same, will still...

Why is the compressor work (steady-flow) proportional to the specific heat of the fluid?

There was a somewhat similar post regarding raising the PSI of a compressor but it doesn't provide an answer to this problem. For various reasons I need to use a very portable cheap tire inflator type compressor. It's ~1 CFM and can inflate to 150 psi maximum pressure (very slowly!). I need...

1. 100kg of methane is compressed from 0.5MPa and 300K to 3.0Mpa and 500K in a closed chamber by a compressor. The compression process is assumed to be adiabatic, calculate the efficiency of this compressor. Specific heat capacity of methane under constant pressure is 35.58 kJ/k.mol.K and ideal...

So, I've recently carried out an experiment to find the volumetric efficiency of a singular reciprocating compressor. During the experiment, there are sub questions asking you to find the value of n and then whether the process is isothermal, poly tropic or adiabatic. Well, n is found to be very...

Homework Statement So, this question is to do with an experiment which investigates the operations of a pneumatic pump. You're asked to find the mass of air displaced in each 30 second period using the atmospheric pressure, temperature and theoretical displacement of the compressor. Also, you...

hi friends, I am confused with incompressible and compressible flow.Can i use moody diagram for air compressor.How can i calculate pressure drop in pipe.

Hello everyone. I'm new to the forum. I'm an engineer...admittedly perhaps not a great one. I wanted to know about a typical automotive fixed geometry turbocharger. Generally it seems that the compressor is larger than the turbine. Despite being more mass flow on the turbine side. :confused...