ENGINEERING.com Mechanical Engineering

Operational Sequence for Fire Pumps

vinodanandan — Mon, 29 Apr 2013 04:06:29 GMT

Hi,
Could somebody guide on operational sequence of fire pumps and jockey.
My specific question is that do Duty and Stand by Fire pumps run together in event of a fire.Do any NFPA clause justify the pump sequence.
Regards,
Vinod

Wire Harness

balu — Fri, 12 Apr 2013 09:53:47 GMT

I want to find the deflection of Wire Harness(Between the two clips) used in car?

also if i want to find deflection of single wire is it possible if i use Beam formula, If beam formula then which formula to be used and how?

eg: electrical wire consists of PVC outer side and copper inside
Then how to find the I-moment of inertia and E- youngs modulus

Thermal Conductivity

dbros — Wed, 13 Feb 2013 04:25:21 GMT

I'm using Q = [2*Pi*k*L*(T1-T2)]/[Ln(r2/r1)] to find heat loss from a pipe. The units for k are W/m*K, the m, meter refers to the thickness of the pipe, the direction of heat transfer. But the L in the equation is the length of the pipe, so I have two units of length, in different dimensions, that don't cancel or match up.

What do I do to get them out of there and have W at the end?

I suspect I'm over thinking this, I know it's not too difficult. Any help is greatly appreciated.

Oil Flow Rate

Noushka — Sat, 16 Mar 2013 01:42:07 GMT

Hi,

Would anyone have an idea how I could estimate the flow rate of Heavy Fuel Oil at the bottom of a pierced tank?

Viscosity: 380 cst at 32 degrees Celsius

I know that
Q=VA and V=(2.g.h)^0.5

But that doesnt account for viscosity...

Thanks.

GIF Ventilated ceiling

icekid — Fri, 15 Mar 2013 23:03:54 GMT

Hi, can I know how GIF ventilated ceiling will comply with NFPA17A. This ceiling is a plenum extract and don't have hood.

Airshower sprinkler protection

icekid — Thu, 14 Mar 2013 01:29:08 GMT

Hi can anyone knows why manufacturer didn't install sprinkler heads inside the airshower. And can I know if this practice is approved on the NFPA

AISI 316L - Detective work :P

floryanatarau — Sun, 10 Mar 2013 22:30:22 GMT

Hi

I have big problem with this material. I need a document which attest that during a Charpy Charpy-V notch testing samples of Stainless steel should support 27J energy at -20 degrees C. This is according to DNV2.9. Do you have any ideea where can I find it , or any clue about it?

Thank you and have a nice week!

how to calculate quantity of hot air to wipe off water

Surender Thakur — Thu, 28 Feb 2013 19:11:53 GMT

how to calculate quantity of hot air to wipe off water over a running strip (In strip processing line?

Actually i have to calculate the capacity of a centrifugal blower in terms of flow and pressure required for a dryer which is to be used to dry strip running at some certain speed. The air from blower is to be heated up with the help of a Heat Exchanger (using steam).

Let us consider the strip is 1mm thk X 1250mm wide and running at 25 Meters per Minute (MPM). Considering blower is distant at 10 meter away with a height difference of 5 Meter from the dryer body. That Means air is to be delivered up to dryer by means of ducts.

The dryer body dimensions is to be calculated. Please help for the same or provide some useful links.

Thanks in advance

Surender Thakur

Shaded pole motor

johir03 — Sat, 23 Feb 2013 20:39:35 GMT

Can anyone help me in manufacturing shaded pole motor

Engine Efficiencies

Peter-27 — Wed, 06 Feb 2013 11:18:58 GMT

I have a little confusion about units.

Working out volumetric efficiency:

(Va+g + nR) / (Vs x N)

That's the formula, and when using Va+g in l/s i'm getting the right answer.

However in part C /(of the same question), thermal efficiency:

Pb / (Vg / Qhv)

I need to use Vg in m^3/s to get the right answer.

These are ratios so obviously units need to cancel, but for the themal efficiency, the units don't cancel. So i'm guessing the problem is that. Can anybody help please?

Fluid Tempature Change Question

hoffkeit — Mon, 11 Feb 2013 09:19:09 GMT

Hello-

I need a little help trying to figure out a fluid tempature change question.

I want to know how much of a tempature change will occur to 3,000 gallons of Jet fuel (stored in a metal tank) that is -4C placed in an enclosed space that is 21C. In that environment, what information would be needed to calculate the change over a 12 hour period? Is is possible?

Thanks!!

NEED SUGGESTION FOR MANUFACTURING

gskssit — Fri, 08 Feb 2013 04:37:59 GMT

Hi,
I want to join two L-angles one across each other with rivets.My problem is while placing one across each other L-angles gets overlapped so here at this zone thickness doubled.i dont want thickness to be doubled so give some suggestions for joining L-angles to the plate with rivets.(Welding is not preffered, only riveting).
Please find the attached file for clear picture.

MEGNET

ZEEL_SHAH — Mon, 07 Jan 2013 00:42:20 GMT

HOW MEG-LEV TRAIN WORK?
AND CAN WE USE THIS TECHNOLOGY IN CAR?
IF WE HAVE 2 OPPOSITION ELECTRIC OR MAGNETIC, WHICH IS ECONOMICAL?

Ideal gas law ?

bonll — Mon, 28 Jan 2013 09:18:04 GMT

In regards to Ideal gas Law / gas constant...

would the statements below be true?

The Ideal Gas Law requires that temperature and pressure be converted to absolute values.
The Ideal Gas Constant R value is: R = 8.3144621(75) J / mol K or
R = 10.73 ft^3 psi / R lbmol

Using ideal gas constant R, ft^3 psi / R lbmol, temperature should be in Rankine(R). Rankine is equal to the temperature in Fahrenheit plus 460. It's also worth noting that mass is measured in pounds mol.

Leak test puzzle?

bonll — Fri, 18 Jan 2013 14:25:38 GMT

Customer leak spec:
External Air pressure of .45 kg/cm2 (6.4 psi), less than 4.5x10-2 cc/sec leakage to the inside of the device.

I need to quantify the amount of bubbles per minute would the leak spec above allow for?
(given that a bubble under water is about 30 - 50 mm3).

(also we leak test in hot water so the opposite of spec).

can someone help provide a solution to this.

Thanks.

bonll

Interview for High School

landylan — Thu, 17 Jan 2013 03:17:35 GMT

I'm doing a report for my highschool engineering class,and I need someone to answer a few questions. You can send a private message(if this site even has that function) to me if that's better for you. My time for this project is almost up. Help!

What were your duties as a mechanical engineer?

What skills were required to complete your job?

What are some projects you have done in the past?

Do you have a lot of freedom with your work?

What do you spend most of your time doing? Are you behind a computer or in a laboratory?

What type of equipment do you get to work with?

Who did you work for?

Is your job dangerous?

What's your work attire?

How hard is it to find a job in your field?

Any pros or cons to the job?

Thanks for your time.

Does anybody knows how to calculate rivet dia for lap joint

gskssit — Tue, 15 Jan 2013 08:06:28 GMT

I have 2.6 mm(2+0.6) thickness of plate for lap joint now i want select the rivet dia. How to calculate rivet dia for lap joint.If anybody knows please let me know.assuming zero load acting on it.????????

Fluid Mechanics

Dioptas — Wed, 16 Jan 2013 00:17:15 GMT

What is differential approach (differential formulation) in fluid mechanics?
What are velocity and acceleration fields, give examples.
Find, study and write down the differential form of continuity equation, Euler and Navier-Stokes Equations in Cartesian coordinates and describe the areas of usage for these equations.

mechanical engineering

satish kumar — Mon, 28 May 2012 10:33:52 GMT

what is the purpose of worm actuator in a butter fly valve

Need help to write a program for meshing

gskssit — Tue, 08 Jan 2013 07:47:58 GMT

Does anybody knows how to write a program for geometric Meshing in c/c++/Patran command language.If so please provide me a solution or else suggest some stuffs to get in.