Thermodynamics entropy problem

In summary, the conversation discusses the flow of air through a pipe with a diameter of 15cm at a rate of 2.3kg/s. The air has an initial pressure of 7bar and temperature of 368K before being throttled by a valve to a pressure of 3.5bar. The data given includes the specific heat ratio (y=1.4), specific heat capacity (C_p=1005J/kgK), and gas constant (R=287). The question is about the downstream velocity and change in entropy. The suggestion given is to use Bernoulli's equation and to provide progress for further assistance.
  • #1
deepthishan
38
0
air flows at 2.3kg/s in 15cm diameter pipe. it has pressure= 7bar and temperature=368K before getting throttled by a valve to 3.5bar.
whats the velocity downstream and the change in entropy??

data: y=1.4, C_p=1005J/kgK, R=287
_________________________________________________

i really am a little lost as to how to proceed
 
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  • #2
Welcome to PF!

deepthishan said:
air flows at 2.3kg/s in 15cm diameter pipe. it has pressure= 7bar and temperature=368K before getting throttled by a valve to 3.5bar.
whats the velocity downstream and the change in entropy??

data: y=1.4, C_p=1005J/kgK, R=287

Hi deepthishan! Welcome to PF! :smile:

Use Bernoulli's equation … if you're still stuck, show us how far you've got, and then we'll know how to help. :smile:
 
  • #3
with this problem.

I can understand your confusion and would like to provide some guidance on how to approach this problem. Firstly, let's define the concept of entropy in thermodynamics. Entropy is a measure of the disorder or randomness in a system. In simple terms, it can be thought of as the level of energy that is unavailable for work in a system. In this case, the air flowing through the pipe is the system.

To calculate the change in entropy, we need to use the equation:

ΔS = m * (s2 - s1)

Where ΔS is the change in entropy, m is the mass flow rate, and s2 and s1 are the specific entropy values at the outlet and inlet, respectively. Since the mass flow rate (m) and inlet entropy (s1) are given, we need to calculate the outlet entropy (s2) using the known values of pressure, temperature, and specific heat capacity (Cp).

To calculate the velocity downstream, we can use the equation:

v = (m_dot * R * T) / (A * P)

Where v is the velocity, m_dot is the mass flow rate, R is the gas constant, T is the temperature, A is the cross-sectional area of the pipe, and P is the pressure.

Substituting the given values in the equation, we can calculate the velocity downstream.

However, it is important to note that the given problem does not specify the type of throttling process (isenthalpic or isentropic), which can affect the accuracy of the calculated values. Additionally, the specific entropy of the air may also vary with temperature and pressure, so it is important to use appropriate values in the calculations.

I hope this explanation helps you in solving the problem. If you need further clarification or assistance, please do not hesitate to ask. I am always here to help with any scientific problems.
 

1. What is the thermodynamics entropy problem?

The thermodynamics entropy problem refers to the concept of entropy, which is a measure of the disorder or randomness in a system. In thermodynamics, entropy is often used to describe the tendency of a system to move towards a state of equilibrium, where all energy is evenly distributed. The entropy problem arises when trying to explain why certain processes or systems increase in entropy, despite the laws of thermodynamics stating that entropy should remain constant or decrease.

2. Why is the thermodynamics entropy problem important?

The thermodynamics entropy problem is important because it has implications for our understanding of the universe and how it works. It challenges our current understanding of the laws of thermodynamics and has led to further research and developments in the field. Solving the entropy problem could also have practical applications, such as improving energy efficiency and developing new technologies.

3. How is the thermodynamics entropy problem currently being tackled?

There are various approaches to tackling the thermodynamics entropy problem, including statistical mechanics and quantum theory. Some scientists also believe that a deeper understanding of the nature of time and space may hold the key to solving the problem. Many ongoing research projects are focused on finding a unifying theory that can fully explain the concept of entropy.

4. Can the thermodynamics entropy problem be solved?

There is currently no definitive answer to whether the thermodynamics entropy problem can be solved. Some scientists believe that a complete understanding of entropy is possible, while others argue that it may be a fundamental aspect of the universe that cannot be fully explained or understood by humans. Ongoing research and advancements in technology may bring us closer to solving the problem in the future.

5. What are the potential implications of solving the thermodynamics entropy problem?

If the thermodynamics entropy problem is solved, it could lead to a better understanding of the universe and how it functions. It may also have practical applications, such as improving energy efficiency and developing new technologies. Additionally, solving the entropy problem could have a profound impact on our understanding of time and space, and may even lead to new breakthroughs in physics and other scientific fields.

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