How can I extract the Nusselt number over time in Ansys for a cavity model?

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Discussion Overview

The discussion revolves around extracting the Nusselt number over time from a cavity model in Ansys, specifically in the context of modeling natural convection heat transfer in a heat exchanger. Participants are seeking methods to visualize the variation of the Nusselt number as time progresses.

Discussion Character

  • Technical explanation, Debate/contested, Homework-related

Main Points Raised

  • One participant describes their process for exporting the Nusselt number using the Reports feature in Ansys but notes it only provides data for a specific time.
  • Another participant suggests that if the convection coefficient (h) can be exported as a function of time, the Nusselt number can be calculated since the thermal conductivity (k) and characteristic length (L) are presumably constant.
  • A different participant questions the use of transient solving and inquires about the total time duration and time step used in the simulation.
  • There is a request for clarification on how to "load the time section" results to plot the Nusselt number or convection coefficient over time.
  • The original poster expresses a desire to obtain the Nusselt number for every time step or specific time steps that can be adjusted.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the method for extracting the Nusselt number over time, with multiple approaches and uncertainties being discussed.

Contextual Notes

There are limitations regarding the clarity of the transient solving process and the specifics of how to extract data over time, which remain unresolved.

alikarimi
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Hi everybody

I built a cavity model in Ansys in order to modelling natural convection heat transfer inside a heat exchanger. But I do not know how to export Nusselt number over time. I need to see how it varies while time passing. Please help me. I know that from Reports part of software I can extract Nusselt number though it is just for one specific time. I need to show its variation versus time.
 
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Can you export h, the convection coefficient, as a function of time? If so then you have your Nusselt number because presumably k and L are fixed.
 
Thank you boneh3ad.

At first I want to check my procedure of exporting nusselt number whether it is true or false:

Reports>Report type>Area-Weighted Average
Field Variable>Wall Fluxes>Surface Nusselt Number

Every time I want to check the nusselt number, I should do the above procedure.

For convection coefficient (h) is the same. I can not draw it over time. I think there should be some method to export Nu or h versus time. Please help me to find it.
 
do you using the transient solve for the this problem, and how much is the total time duration and how much is time step?

For transient solving, you can load the time section(certain times of time step) result and plot the result such as H or Nusselt
 
Thank you chaos_zzy.

What do you mean by "load the time section(certain times of time step) result"?

I want to see the variation of Nusselt number with time. So I should get the nusselt number for every time step (or any other specific time step which I can adjust).

If you have any idea, please send me.
 

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