Questions tagged [airflow]

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58 views

Turbulent boundary layer development in channel flow

I'm currently working on my Bachelor's thesis about the numerical simulation of a turbulent air flow through a rectangular channel. As part of that I'd like to compare my results to empirical ...
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1answer
26 views

What is the most efficient way to heat air?

I'm currently playing with a school project. My goal here is to heat a stream of air to a significant temperature so I can demonstrate air expansion. I have a cylinder, with a few turbines, turning in ...
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2answers
26 views

Will coefficient of discharge remain same when it is used for measuring either liquid or gas flow rate?

I would like to measure air flow rate. I have a orificemeter but do not know its coeficient of discharge. Will the Cd remain same for both the liquid and gases or it will be different.?
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1answer
58 views

Converting flow rate from normal/standard liters per minute to cubic meters per second

I'm really confused about these three units commonly used for measuring airflow: cubic meters per second (m3/s) normal liters per minute (NLPM) standard liters per minute (SLPM) I would appreciate ...
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0answers
30 views

Ducted fan thrust in confined space

I would greatly appreciate any insight into this. I'd like to place a ducted fan inside of a box with the bottom cut out. The fan is attached to the sides of the box by support rods. The ducted fan ...
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0answers
18 views

Can you channel more air into a nozzle by creating a vortex inside of it?

There are designs for ducting in wind turbines to channel a wider cross section of wind into the rotor area. This is unpractical for structural and economical reasons but does actually increase power ...
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3answers
64 views

Which way to put two fans for a wood shop air cleaner - paralel or series?

I'm building a small wood shop air cleaner to suck dust floating in the air. I understand a radial blower (squirell cage) is usually used to get some static pressure to overcome the resistance cased ...
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1answer
19 views

How do I increase negative air pressure without inhibiting airflow?

I would like to increase the vacuum power of my desoldering station. It’s a multifunction unit that includes a single vacuum pickup tool, hot air wand and desoldering gun. When using the desoldering ...
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0answers
18 views

CO2 probe measuring at temperatures up to 150 °C

I'm looking for a $CO_2$ measuring probe (analog current output, digital out: RS232/485 - probe will be connected and transferring real time data to the data logger) that would operate up to 150 °C (...
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1answer
22 views

Climate control in data centers

I'm a student currently working on a market research project on the HVACR industry, and I'm having trouble nailing down a simple answer to these questions (it may be there are no simple answers, as so ...
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1answer
37 views

Why does higher concentration of electonic components decrease the airflow requirement for cooling a PC system?

This source describes in detail a formula used to calculate the airflow requirement in order to cool a computer system. $$Q = \dfrac{P_{loss}}{c_p \cdot \rho \cdot \Delta T}\cdot k$$ Clearly, the ...
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1answer
26 views

At what efficiency does a fan cool a PC case?

A PC case is basically a rectangular pathaway for air to flow through but at the places where the air enters and exits there are solid plastic or metal panels commonly with meshes and little holes. ...
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1answer
22 views

How does fan airflow relate to its RPM setting?

A fan can run at 600 - 2000 RPM, at 2000 RPM it has 50 m3/h airflow. 0% = 0 RPM 100% = 2000 RPM At 50% = 1000 RPM is the airflow halved to 25 m3/h?
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1answer
50 views

How can I calculate the airflow needed for a fan to cool a system?

The airflow needed for a system to sustain itself at 80°C with 25°C ambient temperature can be calculated with this formula: ...
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1answer
15 views

Best Fan Positions for Airflow in a Duct w/ Two 90° Angles

A similar question was answered here. And while that did help me understand airflow, I have an even more specific question with a little different context. So what I'm dealing with here is pulling ...
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1answer
36 views

What is the amount airflow needed from Aquarium Air pump per minute to make a DIY CPAP?

I am trying to make DIY Bubble CPAP that can put a constant pressure on patient. I am using an Aquarium Oxygen pump as air source. The motor says 38L/Min in the spec. And by googling I found that an ...
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1answer
26 views

How can you maximize air flow through a sound maze in a HVAC transfer grille?

My house has several transfer grilles like this: Except they have no baffles inside them, so light and sound come through into our bedrooms quite easily. I'd like to put in a sound maze like this to ...
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1answer
25 views

Cumulative effect of two axial fans

If I already have a small DC axial 2m3/h fan blowing air at something, what will happen if I add a larger more powerful 6m3/h DC axial fan blowing from behind that one (i.e. its the larger fan first, ...
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1answer
38 views

What are the simplest available methods for monitoring pressure and airflow in a 22mm diameter pipe?

In the emergency case that more than one person must share a mechanical ventilator, the medical professionals lose per-patient monitoring of pressure and airflow. To that end, what are the simplest ...
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0answers
306 views

How does the Xbox Series X “Heat-sink chassis” work?

I understand what a heatsink does, but I cannot wrap my head around how the newly announced Xbox Series X's heat-sink chassis works. From Xbox: Heat-sink chassis A heat sink is a non-electronic, ...
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2answers
96 views

What are these outdoors “mystery boxes” for in the USA?

While watching random videos shot in the USA (in the present time), I've noticed these little weird outdoors boxes: What is the purpose of these? They look like they might be related to ventilation ...
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1answer
21 views

How do cavity resonators differ from tubes of uniform width?

I read that wine bottle produces sound when u blow sideways onto its rim because some frequencies of the white noise produced in your mouth gets amplified when they match the natural frequency of the ...
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0answers
23 views

Raining indoors

I have heard stories about buildings such as hangars or large arenas where under the right conditions, clouds could form and it could rain within the building. Is there a specific name for this ...
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3answers
44 views

HVAC Bag Filter Backwash

I need to install a replacement air handler in a facility that has an area where a large volume of particulates are in the air. Unfortunately, the previous designer tried to get away with the ...
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2answers
43 views

How can I build a regulated pressurised air supply?

I need a source of air pressure for an air bearing (3D printed cylinder that expands air upwards like an air hockey table). I would like to be able to control the flow of air. I don't have a lab air ...
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2answers
592 views

What is the equivalent of a capacitor in pneumatics?

I am building a desoldering gun. While the pump I am using provides decent suction, I would like a quick powerful vacuum burst to prevent the solder from solidifying in the nozzle rather than in the ...
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0answers
28 views

Design of fan pipe for propelling glitter

I am trying to create a prototype for a glitter shooting mechanism. It is worth mentioning that I have no experience with mechanical engineering or fluid dynamics. I think the below image describes ...
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1answer
33 views

Does air pressure difference of intake exhaust contribute to jet thrust?

I know momentum of the airflow inside jet engine generates thrust, but what about the pressure difference in front of and at the back of the engine? The air sucking intake at the front has lower than ...
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1answer
36 views

How can I establish as much airflow from my house to outdoors as possible?

I live in a small flat with all doors and windows sealed. The temperature outside is moderately cold. I assume the temperature in my flat is hotter because my body and the computer are emitting ...
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1answer
28 views

How could I automatically agitate water by blowing warm air over its surface?

I want to increase the evaporation rate in a tank by blowing warm air over the surface of the water in the tank; this will (hopefully) agitate the water, increase the airflow in the tank, and maybe ...
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1answer
35 views

Way to digitally measure volume of air inhaled by lungs?

I was interested in this as a fun project. To be able to get the volume of air inhaled by a person has some cool applications I can think of. I was thinking of a modified anemometer of sorts fitted ...
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0answers
52 views

Most efficient turbine for harnessing energy from bidirectional air flow?

I am currently working on designing an oscillating water column as part of a project. In summary: OWC are devices with a semi-submerged chamber or hollow open to the sea below, keeping a trapped ...
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1answer
23 views

Squirrel-cage air blower efficiency

What would be the typical efficiency of a large industrial single-stage squirrel-cage air blower? For example how many kilograms of ambient air (STP) would be moved per second by such blower which ...
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0answers
236 views

Matching Air blower CFM vs HEPA filter CFM, and ΔP in WG, for laminar flow design

I am trying to build a laminar flow box using instructions at these YouTube links for design and build. They recommended getting a Dayton squirrel cage air blower model 1TDU2 rated at 1202 CFM. The ...
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1answer
44 views

Laminar flow hood/air straightener

I was looking at laminar flow filters to aid in my mycology work I'm doing. Most filters use an aluminum extrusion with fins. I figured the options out there are pretty expensive for what you get and ...
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1answer
93 views

How to calculate airflow in m3/min on a gas turbine outlet?

I'm currently trying to figure out the airflow of a gas turbine in m3/min. I thought that i would be able to measure the windspeed over a known cross section on the intakte of the turbine and then ...
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1answer
30 views

What happens in a cone-shaped nozzle?

So I am learning for thermodynamics now and there is one thing that is bugging me. In the book it shows a laval nozzle (very simplified) and a diffuser. with the formulas: (a is the speed of sound) ...
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2answers
59 views

In an air conditioner, how does the released air get cold so quick?

As I understand from reading about air conditioners is that the way they work is that air sucked in from the room is passed by the cold evaporator pipes and then the air is released again. My ...
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1answer
34 views

How to determine ideal flow path length for specified pressure drop

I have designed a flow resistance element and I would like to be able to keep the total pressure drop across the element to < 5.0 inches of water (from 5cc/min to 5,000 cc/min). I have run some ...
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0answers
52 views

Estimating Static Pressure @ Target Airflow (boost fans)

How do I estimate a pressure/flow curve for a filter of specified area, efficiency rating, MERV and MPR?(Duct work is negligible) I am trying to pick an appropriately rated fan/fans to maintain a ...
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33 views

Can I lift 15 tons on air bearings with 0.2 kg air/s?

The air is at 13 kPa and 400 K. I can raise both the supply temperature and the pressure if necessary. No problem with that. I could get 1.7 kg/s for the air bearings, but I have no more air. I ...
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0answers
27 views

Is this is a valid estimation for the mass flow required for Hyperloop air-bearings?

In Hyperloop air bearings, the air escapes through the rear cross-sectional area of each ski, you know? Yes, there is a pressure differential, but the air comes out of the skis, crashes into the tube ...
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2answers
56 views

Would a plane lift from ground if in a free treadmill?

I was wondering if the force generated from the engines of a jet plane would lift it up from the ground if in a free treadmill. Would it take off?
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43 views

Flow Simulation for Laminar Flow in Annular Gap?

Would anyone be able to run an air flow simulation through the following geometry at 100 cc/min? I'm curious if any dead spots occur and if the geometry of the annular gap will produce laminar flow. ...
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28 views

Use of Absolute vs. Differential Pressure Transducers to Calculate Flow Through Annular Restriction

If using a laminar flow element, in conjunction with Poiseuille's equation, to calculate mass and volumetric flow rate, what would the benefit be to using two absolute pressure transducers to measure ...
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0answers
36 views

Is it possible design a portable high powered vacuum cleaner from a 12V DC motor?

I am currently designing a device that can pick up 20 kid's plastic balls from one box and transfer them all into another box. I have decided to use a vacuuming method to vacuum up the balls as my way ...
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3answers
35 views

Is it possible to “expand” air flow area in a duct over a short distance?

Is it possible to increase an air column's diameter over a short distance? Let me explain: Imagine a small 10 cm electric computer cooling fan that's pushing air into a cone-shaped duct 20 cm long. ...
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1answer
966 views

Estimating fan CFM from RPM, HP, and diameter

I am trying to determine the approximate CFM of several axial flow fans being used in agricultural storage in the developing world. The only information the storers have is the power, RPM, and ...
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0answers
25 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
79 views

Noise in centrifugal fan

I'm currently designing my own centrifugal fan for one of my projects, everything excluding the motor. My design is similar to the above just that the outlet is much shorter. The problem I'm facing ...