Airflow Definition and 112 Threads

Blocking the intake of an air flow station I built results in the FPM shooting up along with the vacuum. ie: wide open both ends 4" pipe with inline fan reads . 5" wc / -190 pa / 3700 fpm on instruments monitoring intake pipe. Blocking the intake increases both the vacuum to -470 pa and...

Hi. First post so I hope I have the correct thread location. I am reverse engineering a 40+ year old vertical slide carburettor design i.e. the venturi is horizontal. The current spray nozzle protudes vertically into the airflow but is straight sided and flat across the exit. Option 1...

Hello, I'm a journalist interested in using an air-quality sensor on a drone, and I'm wondering how the airflow will affect the readings. This would be assuming that I will use a DJ Phantom 2 quadcopter with a GoPro underneath, the drone specs can be found at this link. For the project, we...

Hi there, I have recently observed a strange effect regarding a fan and was wondering if someone could explain what's going on. I have a 22cm computer case fan which I am using in a project. For my purposes, I had to partially tape over the back of the fan. I also put a large plastic jar lid...

Why control surfaces are not used below rotor in helicopters?

Heyo, first post here...! Sorry for my English and I will reword anything if it is needed. I've been struggling to solve this for a few days, please help me with some insight or intuition. I have application with a a heating element leading to little ceramic crucible, there is an airflow in and...

Homework Statement Can the power efficiency of the domestic hair dryer be improved by reducing the heat energy and increasing airflow? Homework EquationsThe Attempt at a Solution

The inlet temperature of a baghouse under negative pressure is 400 F and the outlet temperature is 210 F. The volume of air is 10,500 acfm. (baghouse is in poor condition). How do I determine the actual volume given this information?

I'm working on a project now and I'd like to know which type of airflow would power a turbine faster/better straight or rotational? Or will rotational airflow even have any effect on the turbine...? P.S. When I say rotational airflow, I mean circular airflow that rotates in the same direction...

Hi, I am doing an experiment where I am measuring the airflow readings (m/s) of different fans. I then was hoping to use this to work out the force and then from that the power to compare the efficiencies of the different fans. I was wondering if anyone had any suggestions for what equations...

Is there any good approach to determining if an amount of air passing through a given slit or gap will cause a whistling sound? I'm unsure with what shapes whistling might become an issue, and also at what air velocities.

I have a basic airflow question and my mind is in the fog. I'm trying to find the air pressure at a known flow rate and orifice size but I'm having issues with the unit conversions. I'm using Bernoulli's equation Pressure = 1/2 x Air Density x Flow Rate/Area. My Flow Rate is in L/M and the area...

Hi Guys/Girls, Please may I seek your collective minds for help? I have an issue with poor mixture distribution from a carburettor that uses a spray bar and throttle slide (known as a Throttle Body Injector TBI) The holes in the spray bar are at the side of the spray bar in full rich, the...

Hi there, I think this is in the right section if not please inform me and move my thread. I want to design and build a UAV in a copter format whether it be quad, hexa, octa, ect. I want to make a modeling software so that I can design the most efficient blade/motor for my specific needs. I am a...

I spend a lot of time in hotel rooms around the world and the US. The biggest problem I have is with cigarette smoke that comes into my room from the hallway and other rooms. The smoke generally enters my room through the space at the bottom of the door and through the space on the sides. I've...

Can someone shed some light on the following problem? I'm unable to get any traction on it as I know nothing about fluid dynamics (I'm a computer engineer). It's a problem I made up over a lunch discussion with a friend. I've illustrated it as folows:

I know the basic equations for airflow, but for some reason this question has been puzzling me: say you have a copper tube open at one end and connected to a piston cylinder system at the other. Air is drawn through the copper tube and into the cylinder as the piston moves from top to bottom...

Hello everybody, I would like your comments on my findings and perhaps prompt me to look at relevant literature. Consider an enclosed airspace 1m length, 1m height, 0.5m width. At the center of its one 0.5 side a fan is drawing air out of the chamber through an aperture(steady, low air...

Hi, due to the fact that its not my daily work, I how someone could help me to find a startingpoint, how to solve my problem: I want to cool down in a revolver like setup let me say 8 or more cylindrical rods in a continuous way by a counterpropagating airflow. the setup is shown in the...

I have a question regarding the relationship between differential pressure across a filter, the airflow through the filter and the size of the orifice that the aire is moving through. I would like to be able to predict differential pressure required to maintain a constant airflow as the filter I...

This is probably a stupid question but I've been going around in circles for a while now and have gotten myself completely confused. I have a fan and a pump, with performance charts (static pressure vs. air flow) for both. I need to try and determine flow rates for each device when run at...

http://en.wikipedia.org/wiki/Drag_coefficient from wikipedia, it is written 1.98-2.05 for flat plate perpendicular to flow(2D) , but I have a differrent b/h ratio plate, where h=157mm and b=816mm , b/h=5.197 how to get the drag coefficient in this case? Thanks.

I'm making a portable generator box, and I'm currently designing the baffles. The design is quite similar to this: http://media.photobucket.com/image/hush%20box/Audiomechanic/ProjectorHushBox1.png There will be an extra wall on the left and right to accommodate louvres on the exterior...

Homework Statement What we know is that we have two impermeable walls with a porous material inside (the porous material gives a simply restraining force proportional to the movement itself). we have a stationaly flow, so that dw/dt=du/dt=0. u and w are the velocities in the x (horizontal)...

Hello all, I am working on a kit car project that is coming together in a way I had never expected. That preliminary stats are way above what I had expected. So I am getting very excited about completing this project. However now I'm into engineering the radiator its plenum and its...

hello fellow engineers! i just started work at a marine company and was assigned to investigate on this formula. it is from ISO 8861 and used to caculate the airflow needed for heat evacuation in a engine room. this is the formula, airflow needed = (heat emitted from engine and all other...

Hi guys, I need to test the airflow over a wing, I can't find any suitable software to do this job. I heard ANSYS is a good bet, but when I try I'm just lost... (not much exp with it). So anyone got any suggestions to analyse airflow of the wing.

I had a question and I figure you guys are the best for the task. I was wondering if theoretically you had a standard computer case, would you benefit by reducing open airspace in the case? Lets say just for example you could place a cube inside the case that doesn't touch anything, it just...

Hello all! I think I have come to the right place! Can someone explain to a mathematically challenged person such as me which of the following systems would create the most airflow: System #1 - System number one begins with (Point "A") a 1 foot long piece of 2" (I.D.) PVC pipe, connected...

Hi all, long time reader first time poster here. I have a DCBL blower motor that has a fixed wattage at each speed level. I noticed that when I increase pressure (say from 0" SP to .1" SP) the RPM increase and the CFM (airflow) decrease. I understand that CFM will decrease with increased...

When air flows over an airfoil, the air flows at the top flow faster than the bottom and hence creates a net pressure difference, and thus an upward force is applied on the wing. Thus the airplane lift from the ground and keep flying in the air. Now, imagine the side view of a car. Car...

Homework Statement How does the airflow velocity vector get affected by temperature? Homework Equations The equation given is airflow velocity vector is directly proportional to sq.rt of temperature.It says in a jet engine the velocity vector at the compressor rotor blade inlet increases...

Homework Statement not really a question, just stuck with something. An airflow of 300 CFM has a contains 0.0387% CO2 (carbon dioxide-naturally occurring in air) flows through two ends of an rectangular open container from an exhaust fan located at the bottom. Within the container 100%...

I remember once observing a thread in a discussion forum by someone trying to build a backpack helicopter. Various people warned him about sprung-weight-vs-unsprung-weight, hazards of stability and flight control, etc. But ever since reading about James Dyson's bladeless fan and the...

I'm a building contractor looking for a way to measure the airflow (in CFM) of the vent fans that are typical in homes. The usual suspect is in the range of 80-150 CFM, has a squirrelcage fan installed in a metal housing that's installed in the ceiling, and a 3" or 4" round outlet that ducted to...

Hello, I have a question about airflow through a car radiator which has a plate on the discharge side with holes cut for fans. There are fans mounted on there but they aren't being used. And the car is moving. Would the airflow increase or decrease with the plate on there? We are having a...

This inquiry is in relation to internal combustion engines. I am trying to figure out how to maximize the mass of air going into my engine. Because the more air that can get into the cylinder, the more power the motor can make. Now I've been researching Bernoulli's Principle and as I understand...

Ok hopefully one of you can help me out. I have a 68' bug that I recently converted to watercooled with a 2.0 vw engine with a turbo. I have been trying to figure out a way of effectively cooling the motor. I have a single row radiator approx 26'' X 20". I have mounted it in the back of the car...

Hi all, Just Wondering quickly, do the static hub caps on a Formula one car(say Brawn GP) bulge out slightly or are the flat and flush with the wheel? If they do bulge out, why does this produce less drag? Thanks Sean

I am currently a junior in high school in the full I.B. program and I am developing a research question for an extended essay. I have chosen to write an essay in the field of physics, and more specifically, aerodynamics. At the moment, I am trying to conceptualize a working research question...

I have been trying to find some information or study concerning a widely held idea concerning attic ventilation. Conventional wisdom states that when air passes over the ridge vent on the peak of a house, the resulting low pressure will draw air from the attic. The air that is removed from the...

img512.imageshack.us/img512/2985/42904009cw1.jpg Hey guys, I am a bit stuck on this prolbem. When it says identify the characteristic physical scales is this referring only to the length scales (l, h, b)? or is U, gravity, density and viscosity included as well? Now the only two...

AirFlow Calculations/ Anemometer anyone?? Hello all, I am trying to solve a problem with my anemometer. I am not sure if there is anyone here that has used one but here goes. My purpose is to calculate CFM of a particular AIR INTAKE of my truck. The problems lies in that CFM= Air Velocity...

Hi. I am hoping for some advice on airflow...in particular, guaranteeing airflow to a rear mounted radiator, in my 2.5 Triumph Spitfire. I have read, about low pressure, and high pressure areas, although I am a little confused as to the area underneath the car. I understand that the lower a car...

Is there any kind of formula that exists or I can put together that will allow me to determine airflow from a fan being funneled into a tube that decreases in size over the length of the tube? Something specifically that would allow me to determine the air pressure (psi ?) coming out the end of...

I'm setting up a dust collection system for my garage woodworking shop. My plan is to build a manifold for various tools to feed into, with a single 4" exhaust port connected to the dust collector. This manifold is an 8" square by 5' box, with 4", 2 1/2" and 1 1/2" hoses going into it. All...

Hi, I'm a final year Biomed. Eng. student currently working with a team on a project investigating Threshold Responses to Inspiratory loads, and their relation to sleep apnea. The key to this study is a box which provides the loads. It is a rectangular box containing 6 screens or...

Hey, Yet another propeller question on this board. I have done my research, both here & on google, but I cannot seem to find an answer. Lets say I have a motor on which I mount a propeller. This motor is static (not moving like on a flying airplane), so say its a small ventilator...

What makes the air, flow much faster on top of the airfoil, when compared with the bottom surface? In engineering terms, why is there a relatively higher rate of change in velocity over the top surface? and is there any mathematical derivation/proof for coanda effect?

If you wanted to model a filter in an airflow using CFD, how would you go about it? I imagine that an exact model of a filter would be way too complex to model and take vast amounts of time to solve, so there must be some kind of simplification? I was thinking that maybe some known properties of...