Smoke interface height and temperature

In summary, the conversation discusses a complicated calculation involving formulas and graphs related to fires and smoke. The speaker asks for clarification on the labels, units, and formula used for the graph and also questions the meaning of "Th" and the relationship between its temperature and ambient temperature. The other person responds by providing a solution for the graph, explaining that it is a long and difficult process to explain. They mention finding the location and temperature of the smoke interface using two methods and repeating the calculation for a fast growing fire.
  • #1
Sabra_a
33
6
Homework Statement
A warehouse has a floor area of 550 m2 and a height of 11 m. An accidental fire starts on the ground. There is one door opening (3 m high and 6 m wide) at the floor level.

(i) The fire is a steady fire with heat release rate (HRR) 2 MW. Determine, using both the dimensionless method and Klote & Milke’s method, the smoke interface position and corresponding smoke layer temperature and plot them as functions of time from 3m below the ceiling to the top of the opening. Make suitable comments on your results.

(ii) Using one suitable method, repeat the calculations and plot the same as in (i) for a fast growing t^2 fire.
Relevant Equations
Dimensionless method
Klote and Milke's method
Heat release rate
smoke layer height
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  • #2
@Sabra_a
Looks to quite an involved calculation with formulas and graphs.
Unfortunately, I do not have much of the familiarity with fires and smoke to help you out.

But some things I would ask about.

1575744824377.png

What would be the labels on the axis, and units?
From formula does the graph made?

1575745080771.png

Same here - labels and units and formula.

Above the graph is the Th = 36.48 K.
( the previous Th was 290.2 K )
What's Th - the temperature of the smoke?
Is Th supposed to be less than ambient?
 
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Likes berkeman and Sabra_a
  • #3
Thank you fo the reply. I changed few things in my answer
for the graph smoke interface height on the x-axis its time in seconds any y-axis is the smoke interface height
that's my solution. its a really long solution I sill couldn't fit one more page in and it will be difficult to explain. in the first part we are finding the location of the smoke interface and its temperature. its taken from 3 m below the ceiling and above the door which is 6m. this is solved using 2 different methods. them repeating the same calculation for a fast growing fire.
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What is smoke interface height?

Smoke interface height refers to the height at which smoke from a fire or combustion process rises before dispersing into the atmosphere. It is often measured in feet or meters above the ground level.

How is smoke interface height measured?

There are several methods for measuring smoke interface height, including remote sensing techniques such as lidar or radar, as well as direct measurements using instruments such as radiosondes or tethered balloons. These measurements can also be combined with modeling techniques to estimate smoke interface height.

Why is smoke interface height important?

Smoke interface height plays a critical role in understanding the behavior and impact of smoke from fires or other sources. It can affect air quality, visibility, and the dispersion of pollutants in the atmosphere. It is also an important factor in predicting the movement of smoke and its potential impact on human health and the environment.

How does temperature affect smoke interface height?

Temperature can significantly influence smoke interface height. As temperature increases, smoke rises higher and disperses further into the atmosphere. This is due to the fact that warmer air is less dense and therefore less resistant to the upward movement of smoke. Temperature can also affect the buoyancy and stability of the atmosphere, which can impact the behavior of smoke plumes.

What are the implications of changes in smoke interface height?

Changes in smoke interface height can have a range of implications, from impacting air quality and visibility to affecting the spread of wildfires. These changes can also have significant impacts on human health and safety, as well as the environment. Understanding and monitoring smoke interface height is crucial for predicting and mitigating these potential impacts.

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