Questions tagged [compressed-gases]

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Energy required to liquify gaseous oxygen?

Does anyone know where I can find some documentation of a real-world liquification process, and the energy costs? I can calculate the heat that must be removed from O2 gas to get to liquid, but how ...
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1answer
53 views

Recommended books for process engineering? [closed]

I made a career change from machine design to CNG processing. What I’m looking for are some good books/handbooks that cover the following topics. Something similar to Machinery’s Handbook. Piping, ...
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1answer
39 views

Replace Hydrogen in an air cylinder

Can we use a gas cylinder made of A6061, meant to carry air up to 300 bar, with Hydrogen up to the same pressure? If not, what is the maximum pressure that one can safely use hydrogen with?
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2answers
67 views

Time-rate of change of P and T in a pressurized rigid volume with a hole in it

I am trying to model the time-rate of change of pressure and temperature of a gas being held within a pressurized rigid volume as it escapes: an unsteady, open system with no heat transfer. Most ...
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4answers
2k views

Is it possible to increase the heat output of a gas stove by connecting two gas supply canisters to it at the same time, and is it safe to do so?

Here's a typical outdoor gas stove: It is fed by a low-pressure gas supply in the form of a camping cartridge or via an LPG cylinder connected to a low-pressure regulator (around 30mbar) like this ...
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2answers
29 views

What is the purpose of combustor in a gas turbine

I have read online that a gas turbine converts the chemical energy in the fuel gas to mechanical energy of the turbine blades. The way I see it, because of this hot air one would have to go for heat ...
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1answer
23 views

Should pressure vessel head be thicker than wall [closed]

I wondering should the head of a rectangular pressure vessel cylinder be thicker than the wall ?
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1answer
63 views

Relation between Inlet and Outlet mass flow rate for a turbocharger?

For the compressor maps for automotive turbochargers, the Corrected mass flow rate (at inlet) is given as abscissa. However, I wish to know the mass flow rate at the outlet. What is the relation in ...
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0answers
13 views

Skelet Theorie, can anyone help?

I am studying Gas dynamics and came across the lift angle approximation as based on Skelett Theorie (in german). I have done google searches on finding this theory but no luck on any information. Can ...
4
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1answer
29 views

gas regulator exhaust gas during diaphragm adjustment?

On my air tool compressor or scuba gear you can see or hear a diaphragm regulator sloughing off a tiny amount of gas to the atmosphere when you adjust the regulator down. Does a natural gas regulator ...
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0answers
23 views

Can any Air rotameter be used for refrigerant gas by using equation conversion?

Currently, I am trying to find rotameter calibrated for R134A gas flow. However, most companies only sell rotameter or variable area flowmeter for water/Air/Nitrogen flow. Is it possible to use any ...
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1answer
21 views

Real life example of motor/piston involving an isoterm process?

So I am involved in an introductory course in mathematics for pilots. I have the following problem I would like to give them, as it can be a practical application of integration However, does there ...
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0answers
61 views

Injecting CO$_2$ into water: how does injection work?

I've been wanting to design my own water carbonation device for a while. For reference, I've been looking at devices like the Sodastream, which injects pure CO$_2$ into water to dissolve it with up to ...
2
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1answer
84 views

Do pressurised cans still pose a risk to bursting in normal conditions, but after being exposed to heat?

We're planning on shipping some items from the US to Australia as you cannot get them here, that being: https://www.chewy.com/sentry-stop-that-noise-pheromone-dog/dp/56486 I have been in contact ...
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2answers
74 views

Ideal gas law, theory vs reality

I am trying to get an idea of the amount of hydrogen that I can store in some pressurized steel tanks underground. Based on the ideal gas law PV=nRT I did a simple calculation pressure = 200bar ...
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2answers
661 views

Why no hydraulic piston gas compressors?

I've been looking at solutions to compress gases and getting stunned by the cost and maintenance requirements of existing systems to fill cylinders (whether for SCBA or chemical storage) to 2000-...
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1answer
28 views

hydrostatic storage of gasses

This question is a bit general but hopefully someone can point me in the right direction. If you have a metal container, welded shut that's fitted into a hole that is say 10 meters wide and 30 meters ...
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2answers
198 views

Cheapest way to measure gas flow (mass)?

I understand that there are quite a few fairly simple and cheap methods to measure the flow of gas in terms of volume, allowing you to get a flow rate in terms of litres per minute for example. ...
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0answers
18 views

Parts needed for controlling vacuum line pressure with pressurized nitrogen

I'm trying to assemble a simple setup where a line which is typically under vacuum can be pressurized by an external nitrogen supply, with this pressure regulated to less than 1 bar absolute (let's ...
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2answers
2k views

Calculating mass of gas in container

Given pressure is directly proportional to density, my understanding is that you can use the pressure of gas in a container to calculate the mass of the gas in the container. My reasoning being; $p=k\...
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22 views

Modeling Friction-reduced Pressure Drop in Natural Gas Flowing along a Horizontal Cylindrical Trunkline (Pipe)

I am seeking some help related to part of a project I am currently working on, where I require to (data-driven) model the pressure drop due to friction for natural gas flowing along a horizontal ...
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1answer
58 views

Do you adjust gas flow rate (SCCM) to volume of chamber?

If I am carrying out a reaction by flowing 200 SCCM of a gas in a 20mm diameter pipe at 100mm length, if I change the pipe diameter to 10mm: Do I adjust the mass flow rate of the gases? If so, how do ...
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0answers
36 views

How to balance flow and pressure in nitrogen purged chambers?

I have an instrument that is technically a humidity controlled chamber. It measures how much moisture is picked up by the sample through a microbalance(Zone 1). Nitrogen gas flows from zone 3 and ...
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2answers
424 views

Is it standard practice to use a pressure relief valve as a pressure regulator?

I'm attempting to understand the difference between a pressure relief valve and a pressure regulating valve. From my research far, I've come to the following conclusion: Pressure relief valves are ...
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2answers
884 views

Lpg cylinder to compressed air tank

I am building a small robot having pneumatic system. I am using 12v car tyre inflator as my compressor.But i didn't find any 3ltr to 6ltr standardrd air tank. Can i convert my old 3ltr lpg tank into ...
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1answer
1k views

compare l/min output of CO2 pressure reducer to bar (compressed air)

I have a pressure reducer calibrated for Argon and CO$_2$ output. If I connected it to a gas tank with compressed air, how can I convert the output information "liters of Argon / CO$_2$ per minute" to ...
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1answer
322 views

volume comparison of compressed air and gas duster

I'm currently using 400ml Dust Off 67 gas dusters and want to replace them with compressed air and a blow-out gun. In order to select the right equipment and get a better understanding I would like ...
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1answer
2k views

Why was Freon used in spray cans before it was declared a threat to ozone?

I've heard that in the past, spray cans (aerosol cans) contained Freon. I found that the Montreal Protocol made the usage of Freon illegal due to its effect on the ozone layer, but I can't find the ...
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1answer
871 views

Isentropic flow equation derivation

I am trying to derive the isentropic flow equations for a compressible gas by myself and at the end, I have different formulation than the one in the literature. Can you please tell me what am I doing ...
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58 views

Roskam Book equation of dry air density is not clear. I need explanation

Preface: Roskam in book "Airplane Aerodynamics and Performance" explains (in paragraph "1.1 ATMOSPHERIC FUNDAMENTALS"): To determne how water vapor affects air density, consider a given volume ...
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1answer
628 views

Will helium gas lift more weight in air when it is spread over large volume compared to equal weight heavily compressed small volume?

Is it possible for a weather balloons filled with helium gas to lift the weight of itself and a helium tank(highest psi possible) which can fit the volume of the lifting gas in it? Assuming a typical ...
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1answer
7k views

How to determine the choke point in a compressed gas system?

I have a pressure regulator bringing an inlet pressure of 150 bar down to 10 bar which is then lead into a plenum followed by a nozzle of area 340 mm^2, exposed to atmospheric conditions. Weirdly ...
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1answer
65 views

Device (electronic valve?) for controlling O2/Nitrogen levels in sealed chamber

I'm designing an environmentally sealed chamber which will need to have its oxygen level controlled. The chamber has a volume of roughly 1.5 liters. I don't expect pressure to vary too much ... ...
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1answer
857 views

Velocity of flue gases through a pipe

I was wondering if there is any equation that helps to calculate flue gas velocity through a pipe? Can I use the Poiseuille Equation to solve this problem by assuming the flue gas is acting as a ...
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2answers
1k views

What are the advantages of chemical oxygen generation over compressed tank storage?

Chemical oxygen generation (COG) is used in commercial airliners to supply emergency oxygen to passengers and crew if the plane is depressurized. Weight for weight it produces far more oxygen than ...
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1answer
2k views

Valve for mini CO2 gas canister?

I am in the process of helping my son design a sort of model of the Bloodhound SSC car for his school project, using balsa wood, model aircraft wheels, etc... It doesn't have to a like of like, but ...
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2answers
2k views

Air compressor that doubles as a pneumatic motor?

I am working on a compressed air energy storage system. The size and weight of the system are heavily constrained; nothing should (ideally) exceed a few pounds. For this reason, I would like to store ...
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0answers
38 views

Advice on Literature pertaining to transient pipe flow with heat transfer and friction [closed]

For a project I am working on I need to model the flow of argon in a long pipe. The flow is transient in nature since the tanks and regulator from which it enters cause the mass flow to change. ...