Calculate Pressure Due to Heated Water in Tank

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Discussion Overview

The discussion revolves around calculating the pressure exerted by heated water in a closed tank, considering two scenarios: a tank filled completely with water and a tank that is half full. The scope includes theoretical considerations related to fluid mechanics and material properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant asks for help with calculating pressure in a closed tank filled with heated water, specifying two cases: full and half-full tanks.
  • Another participant questions whether this is a homework problem and if any attempts at a solution have been made.
  • A participant clarifies that the inquiry is part of a study, indicating a more formal context for the question.
  • Concerns are raised about the lack of information provided, suggesting that more details are needed to assist effectively.
  • In discussing the first case, a participant proposes assuming atmospheric pressure outside the tank and that the water temperature equals the tank temperature, while also considering the expansion properties of both water and the tank material.
  • It is suggested that if the tank expands less than the water, the water will be compressed, potentially leading to increased pressure and risk of tank failure.
  • For the second case, the nature of the half-full space is questioned, with considerations about whether it contains air, water vapor, or another liquid, and how this affects pressure dynamics.
  • One participant introduces the concept of ullage, suggesting it plays a role in safety and pressure management in the tank.
  • A later reply indicates a possible assumption that the tank volume remains constant and asks if the original poster is familiar with volumetric expansion and bulk modulus concepts.

Areas of Agreement / Disagreement

Participants express differing views on the assumptions that should be made regarding the tank's material properties and the conditions of the water. There is no consensus on how to approach the problem, and multiple competing perspectives remain.

Contextual Notes

Limitations include the lack of specific details about the tank's material properties, the exact conditions of the water, and the assumptions regarding the external environment. The discussion also highlights the need for clarity on the definitions and parameters involved in the calculations.

Muhad
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Hello guys,

I have problem to calculation pressure due to heated water in a closed tank.
1. Tank with full of water.
2. Tank with half of water.

Does anyone has idea?
Thanks a million.
 
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Is this homework? Did you attempt a solution?
 
It is part of study that has been carried out
 
You didn't provide anywhere close to enough information for us to be able to help you. Heck, other than asking for help, you didn't even ask any questions about the issue you are trying to investigate!
 
Welcome to PF.
Muhad said:
I have problem to calculation pressure due to heated water in a closed tank.
1. Tank with full of water.
2. Tank with half of water.
Does anyone has idea?
Can we assume external pressure is atmospheric and that water temperature = tank temperature.
Assume water temperature is liquid and between 0°C and 100°C, or you could have an ice burst or a steam explosion.

Consider case 1.
Assume tank contains no gas bubbles.
What material is the tank made from? Tank expands in three dimensions as it gets hotter. What is expansion coefficient and Young's modulus of tank and of water?
Water in tank expands as it gets hotter. If the water volume expands faster than the tank volume then the water will be compressed and the tank stretched. There will be a pressure in the tank due to those relative expansions and pressures. At some point the tank will burst.

Consider case 2.
Half full of water and half full of what else, air, water vapour or another liquid such as oil?
If other half is a gas then the gas will be compressed or rarefied to make up for the differential expansion of tank and liquid. The solubility of gas in water may be important.

Ullage is not always bad, it is essential to safety. Look up the word ullage.
See also; https://en.wikipedia.org/wiki/Ullage#Industrial_use
 
In case 1, I think they want you to assume that the tank volume does not change. You are starting with pure liquid. Are you familiar with the concepts of coefficient of volumetric expansion and bulk modulus?

Chet
 

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