How Do You Calculate Pipe Temperature with Uniform Heating Over Length?

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Discussion Overview

The discussion revolves around calculating the temperature distribution of water flowing through a heated pipe. Participants explore the implications of given parameters such as temperature, pressure, pipe diameter, heat flux, and mass flow rate, while considering the effects of flow regime on the calculations. The scope includes theoretical modeling and potential application in a homework context.

Discussion Character

  • Homework-related
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant presents the problem and requests assistance in calculating the temperature along the pipe and plotting it as a function of pipe length.
  • Another participant questions the approach, suggesting that the problem may be overspecified due to the simultaneous specification of mass flow rate and pressure drop.
  • A participant outlines the energy balance equation and proposes a method to calculate temperature distribution, indicating a linear relationship along the pipe.
  • There is a suggestion to determine whether the flow is laminar or turbulent by calculating the Reynolds number, which would influence the choice of equations for heat transfer.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the flow regime and its impact on the calculations. There is no consensus on the correct approach to solving the problem, as different methods and considerations are proposed.

Contextual Notes

Participants note the need to clarify assumptions about flow characteristics and the implications of given parameters on the calculations. The discussion highlights the complexity of heat transfer in fluid dynamics without resolving the mathematical steps involved.

Who May Find This Useful

This discussion may be useful for students or practitioners interested in fluid dynamics, heat transfer, and thermal analysis in engineering contexts.

wasaimal
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is anyone help to solve this problem?

Water at a temperature of 20degree C and a pressure 8 bar enters a pipe of dia.0.2 cm.The Pipe uniformly heated with 5.0kW/m². Calculate the Temperature along the pipe for the pipe length of 20m. plot temperatuer as a function of the pipe length. m=0.5 kg/s

wasaimal@hotmail.com
 
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This is obviously homework, what are your thoughts on how it needs to be solved?
 


I have no clue
 


Given
T_in = 20 C^0 Heat Flux = 5.0 kW/m^2
D = 0.2 cm X = Length = 20 m
Pressure = 8 bar Area = (πD^2)/4 = (3.14〖(0.002)〗^2)/4 = 3.14E-〖10〗^6 〖 m〗^2
Calculate
Calculate the Temperature along the pipe for the pipe length.
Plot Temperature as a function of the pipe length.
Energy balanced equation is valid for ant pipe length.
q’ (X) = m ̇ C_p (T_x - T_in)
T_x = T_in + (q’)/(mC_p ) ̇ X
= 20 + 0.0157/(0.5)4180 X = 20 + 7.511E-〖10〗^6 X (It’s a linear distribution along the pipe).

any one check and if i am on correct path?
 
wasaimal said:
is anyone help to solve this problem?

Water at a temperature of 20degree C and a pressure 8 bar enters a pipe of dia.0.2 cm.The Pipe uniformly heated with 5.0kW/m². Calculate the Temperature along the pipe for the pipe length of 20m. plot temperatuer as a function of the pipe length. m=0.5 kg/s

wasaimal@hotmail.com

It looks like the problem is overspecified. You can't specify the mass flow rate if you give the pressure drop (presumably 7 bars).

You first need to get a handle on whether the flow is turbulent or laminar by approximating the Reynolds number. If the flow is laminar, Bird, Stewart, and Lightfoot gives the solution for constant flux laminar flow heating of fluid flow in a tube. If the flow is turbulent, they give the equation for the Nussult Number (dimensionless heat transfer coefficient) as a function of the Reynolds Number and Prantdl number.
 

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