Unsolvable Mechanical Engineering Questions: Dredging and Pipeline Capacity

  • Thread starter vzaia86
  • Start date
In summary, the conversation involves two questions related to a structural engineering project. The first question discusses the challenges of pumping sand to a height of 70m and then horizontally for 5km. The second question pertains to the necessary pump pressure for a certain water capacity when the pipeline diameter is found to be smaller than expected. Solutions are suggested for both questions, including considering material dynamics and pipe friction, as well as using Reynold's formula and increasing engine power.
  • #1
vzaia86
1
0
To all mechanical engineers,

I have two questions I cannot answer in my structural 4th year project. They are not structurally related, but more mechanical. Can anyone please help. Thanks. I don't know why the give structural engineers these questions at university?

1)A dredger has to pump sand to a height of 70m (cliff) above sea level firstly and
from there another 5 km horizontally to an inland reclamation area. The inboard
pumps of the dredger can provide just sufficient pressure to bring the material to
the top of the cliff with the minimum required speed. What to do? Also think of
the dynamics of the process. What details would you keep an eye on?After having
pumped 50% of the required quantity, material starts to become coarser. What are
the consequences? How to resolve?

2) You need to deliver a certain capacity (m3/s water). You have designed a pump
and pipeline and you have submitted a plan. However, when the actual delivery
has to start, the pipeline diameter is measured and it is found that it is 95% of
what you had designed. How much additional pump pressure is required to
deliver still the same capacity. How can you achieve that?
 
Engineering news on Phys.org
  • #2
vzaia86 said:
1)A dredger has to pump sand to a height of 70m (cliff) above sea level firstly and
from there another 5 km horizontally to an inland reclamation area. The inboard
pumps of the dredger can provide just sufficient pressure to bring the material to
the top of the cliff with the minimum required speed. What to do? Also think of
the dynamics of the process. What details would you keep an eye on?After having
pumped 50% of the required quantity, material starts to become coarser. What are
the consequences? How to resolve?

2) You need to deliver a certain capacity (m3/s water). You have designed a pump
and pipeline and you have submitted a plan. However, when the actual delivery
has to start, the pipeline diameter is measured and it is found that it is 95% of
what you had designed. How much additional pump pressure is required to
deliver still the same capacity. How can you achieve that?

1) A problem of viscosity and lot of stuff. I hope the dredger is land based as if not it would not be able to pump the 5 km inland. If so use steps, pump up to 50m first, move the dreger there and from then on to the end. Coarser might be easier to move if I remember it right, but without knowing any material data that is a mystery. Pipe friction for the 5km inland pipe might be harder then the 70m ascent.

2) Smaller pipes have more friction so more pressure needed for the same capacity, look into Reynold's formula for this kind of stuff. About how you can achieve your goal, considering that most land based stuff is engineered with a safety factor of at least 2 the pump might do just fine with a little more engine power.
 

1. What are the two questions you cannot answer?

The two questions I cannot answer are subjective and personal to me. As a scientist, I focus on objective and measurable research questions and do not engage in speculation or assumptions.

2. Why can't you answer these two questions?

I am limited by the scientific method, which relies on empirical evidence and observable data to draw conclusions. The two questions I cannot answer do not have a clear answer or evidence to support them.

3. Is there any possibility of finding the answers to these questions in the future?

It is always possible for new research and discoveries to shed light on previously unknown information. However, the two questions I cannot answer may not have clear answers that can be scientifically proven.

4. Can you give any hints or clues about what these two questions are?

I prefer to keep the nature of the two questions I cannot answer private, as they are personal to me and may not be relevant to others. As a scientist, my focus is on sharing and discussing objective research and findings.

5. Does not being able to answer these two questions affect your credibility as a scientist?

No, my inability to answer these two questions does not affect my credibility as a scientist. As a researcher, I am trained to acknowledge and work with uncertainty and unknowns. It is important to be honest and transparent about what we do and do not know in the scientific community.

Similar threads

  • Mechanical Engineering
Replies
11
Views
1K
Replies
10
Views
899
Replies
5
Views
2K
  • Mechanical Engineering
Replies
1
Views
745
  • Mechanical Engineering
Replies
2
Views
1K
Replies
10
Views
2K
  • Mechanical Engineering
Replies
14
Views
2K
  • Mechanical Engineering
Replies
2
Views
2K
Replies
11
Views
3K
  • Mechanical Engineering
Replies
3
Views
1K
Back
Top