How to Calculate Velocity and Entropy Change in Throttled Airflow?

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SUMMARY

The discussion focuses on calculating the downstream velocity and entropy change of air flowing through a 15 cm diameter pipe, initially at 7 bar and 368 K, which is throttled to 3.5 bar. The mass flow rate is 2.3 kg/s, with specific heat capacity (C_p) of 1005 J/kgK and gas constant (R) of 287. Participants recommend using Bernoulli's equation to derive the necessary calculations for velocity and entropy change in this throttled airflow scenario.

PREREQUISITES
  • Understanding of Bernoulli's equation
  • Knowledge of thermodynamic properties of gases
  • Familiarity with the ideal gas law
  • Basic fluid dynamics concepts
NEXT STEPS
  • Calculate downstream velocity using Bernoulli's equation
  • Determine entropy change using the formula for isentropic processes
  • Explore the implications of throttling on airflow dynamics
  • Study the effects of pressure and temperature changes on gas properties
USEFUL FOR

Mechanical engineers, thermodynamics students, and professionals involved in fluid mechanics and HVAC systems will benefit from this discussion.

deepthishan
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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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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:
 

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