Fluid Mechanics: Choosing a fuel line diameter for a required pressure drop

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Discussion Overview

The discussion revolves around a homework problem related to fluid mechanics, specifically focusing on selecting an appropriate fuel line diameter to achieve a required pressure drop. The conversation includes the application of relevant equations, assumptions about flow types, and the calculation of pressure drop in pipe flow.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Participants discuss the need for a more descriptive thread title to attract appropriate assistance.
  • One participant requests the relevant equations and definitions of variables to clarify the problem.
  • A specific pressure drop equation is presented: P=32 x w x Vavg x L / D^2.
  • Concerns are raised about the assumption of laminar flow, with a suggestion to calculate the Reynolds number to determine flow type.
  • Confusion is expressed regarding the next steps after calculating the Reynolds number.
  • Questions are posed about the method for calculating pressure drop using the friction factor and Reynolds number.
  • Participants challenge the realism of a flow velocity of 524 m/s and inquire about the source of the diameter value used.
  • One participant indicates a lack of familiarity with the equation for pressure drop involving the friction factor.

Areas of Agreement / Disagreement

There is no consensus on the assumptions regarding flow type, the calculations presented, or the methods to be used for determining pressure drop. Multiple competing views and uncertainties remain throughout the discussion.

Contextual Notes

Participants express uncertainty about the applicability of certain equations and the realism of calculated values, indicating potential limitations in understanding or assumptions made in the problem.

NickH21
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Homework Statement

[/B]
DB12A289-8491-4A73-A393-066E40D79639.jpeg


Homework Equations

- The pressure drop equation. [/B]

The Attempt at a Solution


10A0EB59-5CCC-4C30-A075-E20471C5A1CB.jpeg
 

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Hi NickH21,

Your thread title is too general. Please make sure that your thread title is descriptive of the actual problem so that the Homeowrk Helpers with the correct skill set can quickly spot your thread. This time I will change your title to read: 'Fluid Mechanics: Choosing a fuel line diameter for a required pressure drop'.

Can you type out your Relevant equation(s) and define the variables? There are several possible pressure drop equations.
Can you explain where the numbers come from in your attempt? There isn't an obvious correlation between them and the given values in the problem statement; is there more work you haven't shown?

Also, Please take a moment to read the thread, Guidelines for students and helpers, which you can find pinned at the top of each of the homework forums. It gives an overview of how to create an effective homework help request following the posting rules.
 
P=32 x w x Vavg x L / D^2
 
You seem to be assuming you have laminar flow, when the problem statement strongly hints that the flow is turbulent. Have you calculated a Reynolds number?
 
Chestermiller said:
You seem to be assuming you have laminar flow, when the problem statement strongly hints that the flow is turbulent. Have you calculated a Reynolds number?
Yes. I’ve got my Reynolds number, but that’s where I’m confused at. I just don’t know where to go from there.
 
Are you familiar with how to get the pressure drop in pipe flow using friction factor and Reynolds number?

Where did you get that value for the diameter from?
Do you really think that a flow velocity of 524 m/s is realistic?
 
Chestermiller said:
Are you familiar with how to get the pressure drop in pipe flow using friction factor and Reynolds number?

Where did you get that value for the diameter from?
Do you really think that a flow velocity of 524 m/s is realistic?
I’m not to sure how to find the pressure drop with the friction factor. I’m not familiar with that equation.
 
NickH21 said:
I’m not to sure how to find the pressure drop with the friction factor. I’m not familiar with that equation.
Then you need to find out about it in your fluid mechanics book, or wherever this problem came from.
 

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