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19 views

Chemical reactions in fluids

The equations of motion of ordinary relativistic hydrodynamics are derived by considering conservation equations of the energy tensor and particle number current, where constitutive relations relate ...
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1answer
181 views

What's the minimum time scale for a candle to be lit in order for it to establish a steady state?

My Understanding When a candle is lit initially, it goes through a few stages (see, e.g. this explanation from the National Candle Association): Wick burns. Crusted wax on wick melts, evaporates ...
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0answers
21 views

Convert Normal water to cool instantly [closed]

Is it possible to convert the hot/normal water to cold steam instantly(may be within 1/2hr) without using refrigerators etc. If yes, how far can the cold steam travel. I am not sure with all the fluid ...
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4answers
2k views

How does the dissolution of salt affect the solution density?

Suppose you have a container of water as a solvent and you a certain amount of salt as a solute sitting at the bottom of the container that has yet to start dissolving. Supposing temperature and ...
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1answer
35 views

Does the presence of a flame affect the flow rate of gas out of a lighter or torch?

If I were to set a propane torch's valve to a fixed open position, would it run out of gas faster lit or unlit? Does the flame produce any kind of pressure change that affects the flow rate through ...
1
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1answer
59 views

Water Bottle Condensation

My friends and I were at a party last night and we were crushing empty water bottles until the cap popped off and water vapor came out. I have two questions regarding this phenomenon. From previous ...
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1answer
54 views

Meaning of extraction ratio $E=\frac{C_{Ai}-C_{Ao}}{C_{Ai}-C_{Bi}}$

My goal is to understand the meaning of the extraction ratio (artificial kidney, not other systems). I have the system in figure ($Q$ volumetric flow, $C$ concentration, the red line is a permeable ...
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0answers
35 views

Smallest Aperture for $HCl$ to pass through [duplicate]

What is the smallest aperture that hydrochloric acid could pass through, such that the acid's surface tension wouldn't be stopping it from flowing through? Also, how would I work that out? I'm testing ...
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2answers
89 views

What does pressure of a gas really mean, is it the Pressure applied on the gas or the Pressure exerted by the gas on some boundary?

In Ideal Gas Equation $PV=nRT$ , $P$ is the pressure the gas exerts on the walls of the volume it is bounded in. But i've seen in some problems it is stated that the gas is under a pressure $ x$ $ N/m^...
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2answers
3k views

Physical reason of adding salt when we're cooking rice (osmosis)

Why do we add salt when we're cooking rice? I know one reason is related to the boiling point of water but someone said it is also related to "Osmosis". What is the relation between adding salt and ...
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1answer
78 views

Modeling the dissolution of an oil droplet with detergent

How to model the dissolution of an oil droplet on the surface of water when a detergent is (gradually) added to the water? I believe this includes an interplay of coalescence keeping the droplet ...
2
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1answer
121 views

Why is it easier to remove stains with water?

And I don't mean stain removers, but literally tap water. See here's the thing, you can't remove a stain without some sort of friction, and water reduces friction. Yet if I say, spill some coffee and ...
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1answer
862 views

Gas permeation through solid metal?

If I make a box from aluminum (0.5 mm thickness) and put air in it (about 2 bar or 3 bar), would the box lose the air over time (10 years period) or not? Assuming the temperature will change ...
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1answer
62 views

How much approximately the pressure would drop?

A container made from from aluminium ($0.5~\mathrm{mm}$ thickness $10^3~\mathrm{cm^3}$) closed system , it has 50 psi (nitrogen) pressure inside at temperature $80^\circ~\mathrm C.$ Approximately : ...
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0answers
50 views

Is Gas flow rate or Volumertric flow rate right one to use for thick wall?

I will make container from steel or aluminium ( 0.5 mm thickness ) and fill it with air (2 bar) and I want to know how much pressure would the container loose overtime (20 years) ? I have asked this ...
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2answers
74 views

How much pressure would I lose on one side?

The equation for the gas flow rate (in pressure*volume/time units) $$ Q = {kA\over d} (p_1-p_2) $$ where $A$ is the surface area, $d$ the wall thickness, $p_{1,2}$ the pressures on either side of the ...
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1answer
134 views

why do microscopic cracks happen?

2 weeks ago i asked a question about " Gas permeation through solid metal? " i have got a very good answer here .but microscopic crack was mentioned in the answer. i searched in Internet but i didnt ...
6
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3answers
8k views

How much heat from a fire actually warms your home?

A fire in a hearth disperses heat to, I guess, three places: the bricks of the chimney out the hearth (where the person tending the fire is standing) out the chimney, above the house How would you ...
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1answer
175 views

Physics behind blowing soap bubbles

Is it possible, using the surface tension of a soap bubble, to calculate the maximum pressure (created by the air flow) it can withstand while still attached to the orifice to prevent it from bursting?...
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0answers
271 views

How does fluid velocity affect the dissolution of some solute in the fluid?

Suppose we have a perfect sphere of some solute such as sugar and we place it in a fluid such as water, at a certain temperature, that is not moving. It will dissolve and diffuse into the water due to ...
3
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2answers
3k views

Gas viscosity at high pressure, high temperature

EDIT 1 PER COMMENTS I am wanting to model nitrogen gas viscosity as a function of pressure and temperature OR learn of an existing equation that models nitrogen viscosity for the pressure and ...
1
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1answer
319 views

Smoothed Particle Hydrodynamics, Chemical Reactions and Stiffness [closed]

Dear people from stackexchange physics. I have been using SPH for quite a while to simulate free boundary flow, and just recently we tried to include some kind of (simple) chemical reaction in our ...
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0answers
268 views

Leakage rate Calculation

I have to calculate leak rate for helium/air from an enclosure which is made of fabric. This is similar to helium balloons. There are small holes in the fabric. How should i proceed ?