Questions tagged [gas]

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21
votes
3answers
1k views

How to know whether the flow is supersonic in a nozzle?

For a project I had built a convergent divergent nozzle designed for Mach number = 3. In that project, I could know the flow has gone supersonic by seeing the manometer fixed between the throat and ...
9
votes
2answers
429 views

How is gas flow through (extremely long) pipelines monitored and controlled?

(This is closely linked with measuring the Mach number inside a nozzle but it is not regarding the supersonic flow) Friction and heat transfer have effects on the Mach number of the compressible flow ...
7
votes
1answer
187 views

Can using different types of alcohol in a cloud chamber produce different particle tracks?

The design for a cloud chamber is rather simple, and many factors can be changed without producing different results. There is one curious point that I've stumbled upon, though: The type of alcohol ...
6
votes
1answer
104 views

Multi-gas barometric height formula in isotope separation devices?

I think, actually the first row is needed is a barometric height formula for the mix of gases. The main problem I can see, the curves describing the minimal energy (kinetic + gravitational/...
5
votes
4answers
178 views

Determining pressures of a compressible gas

A friend and I wrote a paper for a fluids class discussing the details (as they relate to fluid dynamics) of constructing a cannon that could shoot a steak fast enough to cook it. We quickly ...
5
votes
1answer
67 views

Easily compute a good approximation of heat conductivity of cooled semi-vacuum (water vapor + air)

I am preparing a classroom demonstration about heat, including a demo of how a satellite loses heat only radiatively, since it's flying through a vacuum. I'd like to make the vacuum-production ...
5
votes
1answer
716 views

How do gas flow regulators avoid choking?

According to compressible flow theory, a downstream pressure of 0.528 times upstream pressure is sufficient to choke a flow device. So, how do industrial grade pressure regulators throttle a wide ...
5
votes
2answers
926 views

Pressure drop due to mass loss

How can I "tie" pressure change due to a mass leakage from the flow? In a "closed" system I'd use $pV=nRT$ but this is an "open" system... My open system is an horizontal (no gravity issue) pipe (...
4
votes
2answers
156 views

Is steel air (argon) tight?

I need to build an air tight system that can hold gas (Argon Gas). I see that most pipes use steel. Is steel tight enough to hold that gas? Argon is very dense, so I think it should have no problem.
4
votes
2answers
100 views

Can cyclonic separators be used to separate heavier and lighter gases?

I'm trying to increase the Helium detection capabilities of a sniffer unit. Could a cyclonic separator, like that used in the oil/gas industry, with enough fluid velocity move the heavier gas ...
4
votes
1answer
663 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 ...
3
votes
1answer
58 views

Would pumping down (below 0 psi) on a gas cylinder regulator cause it to break?

Would pumping down on a gas cylinder regulator cause the needle of the valve to break since it’s trying to go below zero? Would this also cause a problem with the regulator itself? I’ve included the ...
3
votes
1answer
126 views

Can mercury escape undectectably from a CFL bulb? or does it have to shatter for the mercury to be liberated?

I read that the mercury vapour inside a fluorescent lamp is pressurized at 0.2% of atmospheric pressure. Can mercury escape undectably through a small crack in the glass yet still light up? Or will ...
3
votes
1answer
168 views

Service Life of a Flashback Arrestor

First of all, I would like to know about the service life of a flashback arrestor. In my laboratory, I got three flashback arrestors {WITTgas RF53N(1/4”NPT-F), Brass} from the ex-students who used ...
3
votes
1answer
4k views

Working out pressure drop from leak rate

I am trying to work out the acceptable pressure drop/increase on a leak test rig for a given leak rate. A simplified version of the test rig looks like this: The gas (air) supply is at 1 bar above ...
2
votes
2answers
2k views

Typical power consumption of large compressor

This one should be easy to answer by looking at the thermodynamics, but I find it not to be. Say we have a natural gas stream, ~700 N∙m3/h, that we want to compress from 16 bar to 250 bar. What will ...
2
votes
2answers
8k views

What material is used to make gas pipes?

What is the most common material gas pipes made of? I read in a unreliable website it's steel, is it true? Also how good is steel at stopping or slowing down the leaking of gas? The gas I am ...
2
votes
1answer
54 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 ...
2
votes
1answer
286 views

Is an Explosion Proof Circuit Breaker Panel Required at a Gas Station?

Check the attached photo of a gasoline station. The two panel boxes at the center of the photo (in the corner of the station) are standard panels (IP-67), which enclose standard circuit breakers for ...
2
votes
2answers
622 views

Pressure drop across column in gas phase: what changes?

If you force high-pressure gas through a packed-bed, the gas pressure drops. However, the ideal gas law states: $$P = \frac{RT}{v}$$ so for an ideal gas, the pressure drop must be associated with a ...
2
votes
2answers
331 views

What is a reference that i can use to find the interpretation of a symbol in a gas line schematic?

I have a schematic for some gas lines in a wafer processing unit. One of the symbols which occurs is a circle with an x in it that has the left and right quarters filled in to form two black ...
2
votes
2answers
517 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 ...
2
votes
2answers
44 views

Can I improve this exhaust gas probe to be immune to pressure changes?

I'm designing a probe to provide a stable and continuous stream of exhaust gas sample to an analyser. The probe has to be inserted into the exhaust for about 20–30 cm to keep outside air from entering ...
2
votes
3answers
10k views

How to calculate the velocity of gas in a pipe?

I was wondering how I can calculate the velocity of gas through a pipe. The gas, assuming ideal behavior, in a pipe (cylinder) of volume of 222.4 L has a pressure of 1.95 atmospheres and a density of ...
2
votes
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
votes
0answers
16 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 ...
2
votes
0answers
30 views

Liquid phase gas flow through valve

I have been trying to figure out how to calculate the required dimensions for liquid phase gas through a solenoid valve. Many companies (Swagelok, Bürkert, Asco) provide "Flow coefficient calculators" ...
2
votes
0answers
39 views

Oxygen sensors in trace gas environments

Do Oxygen lambda sensors (used in automotive applications) work in trace gas environments? My requirements for a trace Oxygen gas sensor: The sensor must be capable of working in an inert gas ...
2
votes
1answer
371 views

What are the differences between compressor stations, pump stations, and booster stations?

I am doing some research on impacts related to natural gas compressor stations. In some states, I've received data for compressor stations alongside other facilities in the oil and gas world. These ...
2
votes
0answers
51 views

Ambient helium level monitoring

I am looking for a solution to monitor and log ambient He levels down to 50-100ppm. The detector is meant to be installed in an experimental hall where a large number of Photo Multiplier Tubes are ...
1
vote
1answer
1k views

How can I turn home gas (LPG) from liquid to gas?

"LPG" is the term used here for a mixture of Propane & Butane sold for public use. The exact ratio varies depending on where you buy it and I think also with the season and is not known to me. I ...
1
vote
2answers
1k views

How do you prevent ignition of the gas-air mixture before it reaches the burner nozzle?

I believed that the flame propagates over the place where fuel contacts the oxygen. If it contacts a fule+O2 mixture, the mixture inflames as well, and so on and on and on until there is no more ...
1
vote
2answers
2k views

Diesel or Gasoline? Which one is more dangerous to our health?

I have an overall question that's been bothering me for years. Which is more dangerous for our health, a diesel car or a gasoline car? This is quite a cliche question and I can find a lot of ...
1
vote
1answer
51 views

Is there any option other than a gas welder

I want to repair a dent in a piece of cast iron with brass. I want to fill the site with brass. For some reason, I want to do it by myself. I can buy an instrument for this work in a limited budget(...
1
vote
1answer
69 views

Calculate pneumatic cylinder dimensions from work done

I have a project for which I need a pneumatic cylinder to impart an impact force in such a way that work-done/energy is 4.5 Joules, and the input pressure is 10 bar. How can I solve this so that I ...
1
vote
2answers
59 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. ...
1
vote
2answers
53 views

Is there an optical technology able to measure the temperature of dry air?

Optical IR sensors are able to measure the surface temperature of solids. But is there a range of the EM spectrum that can accomplish the same for measuring the temperature of nitrox (dry nitrogen, ...
1
vote
1answer
70 views

Why is gas pressure specified instead of mass flow?

Clarification: This question is all about the gas supply to the water heater. It has nothing to do with the water supply. My hot water heater specifies 5.5-10.5 W.C. (water column inches) of pressure....
1
vote
1answer
540 views

Difference between gas combustion engine and gas turbine?

I am a non-engineer and I am using a gas power plant data base. Some plants listed are of the type "combustion engine", some of the type "gas turbine", some "steam turbine" and some "combined cycle". ...
1
vote
1answer
79 views

Helium is leaking through manometer

I have connected a 200 bar helium tank and a manometer to a pressure regulator. The end of the manometer's tube connected to the regulator is leaking. It's attached with anaerobic thread sealant, so I ...
1
vote
1answer
84 views

Pressure Differential Analysis

In these units: cm³.20μ/m².24hr.atm - (definition) cubic centimeters for a 20 micron film thickness per square meter per 24 hours under a pressure difference of 1 atm. My question is what does the "...
1
vote
1answer
210 views

How to calculate propulsive force of gas ejection

How can I calculate the propulsive force produced by ejection of a gas? I suppose it depends on the gas, the velocity with which it ejects, the amount of gas, and some other parameters, like the ...
1
vote
1answer
26 views

Valve/Filter allowing through gas only, no liquid

I need to devise a way to ensure only NG passes through a pipe, and no condensates or other liquids. It is ok to shut down the pipeline if liquids would be detected. The dimensions involved are small ...
1
vote
0answers
23 views

Equation for temperature of gas at Joule-Thompson Inversion State

Assume that a gas obeys the following equation of state: $\nu = {\frac{RT}{P}}-{\frac{a}{T}} + b$ Where $a , b $ are constant. Derive an equation for the temperature at the Joule-Thompson ...
1
vote
1answer
84 views

Which type of sensors to analyze polluting gas from vehicle emissions

I am thinking to develop a remote-sensing applications for vehicle pollutions. In such cases generally expensive optical IR and UV devices are used because more precise. These devices are generally ...
1
vote
0answers
53 views

Is there a 5% range CO sensor with a response rate higher than 1Hz?

I'm building a portable emission analyser which measures emissions from a tailpipe, to aid in troubleshooting and tuning an engine. For this, I need a $\text{CO}_{2}$ , a $\text{CO}$, and an $\text{O}...
1
vote
1answer
255 views

What ramping constraints for gas plant - CCGT, combustion and steam turbine?

I am using the publication Current and Prospective Costs of Electricity Generation until 2050 to source ramping constraints for an economic model of three different gas power plants - CCGT, combustion ...
1
vote
0answers
89 views

Creating a “pinhole” small enough to allow only one molecule to pass through

Consider a "cartridge" of sorts. Is it possible to construct a "pinhole" in the cartridge such that only one molecule will pass through at a time? If so, what sort of equipment would I need to ...
1
vote
0answers
21 views

Spades used in pressure testing PE Pipe lines [closed]

As we all know the industry is heading into PE pipelines in the gathering fields fast. Some applications use DN560-DN1000, and the spades is very heavy and in awkward positions. Is there PE spades/...
1
vote
0answers
43 views

How to convert permeation units to molecules/second?

How do I convert $\dfrac{\text{cm}^3\cdot\text{mm}}{\text{m}^2 \cdot \text{day} \cdot \text{atm}}$ for permeation of gas through EVOH to molecules of gas permeating per second as a function of ...