Average Heat Flux
Express heat transfer rate per unit surface area.
Try this formula
Calculate average heat flux or choose another supported quantity.
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Try this formula
Calculate average heat flux or choose another supported quantity.
Use decimals or scientific notation, such as 1.2e3. Calculations update as you type.
Average heat flux
Enter the known values to see the result.
Use the surface area associated with the stated heat transfer rate. For a nonuniform distribution, this is the area-averaged flux. Positive direction must be specified consistently for rate and flux.
Difficulty
Beginner
Read time
4 min
Prerequisites
Basic algebra, mechanics, and consistent SI units
Source
Teng-Jui Lin — CHEM E 330 — Transport Processes IReference equation: Heat flux. FormuLab wrote new explanations, assumptions, applications, and numerical examples.
Adapted from Teng-Jui Lin, Equation Sheets — Mechanical Engineering Expansion, under CC BY 4.0.
Adapted standard equations and added original lesson text, variables, SI examples, and assumptions.
Definition
Heat rate describes energy per second for an entire surface. Heat flux divides that rate by area, making it possible to compare thermal loading of differently sized surfaces.
Variables & Units
| Symbol | Meaning | Units |
|---|---|---|
| Average heat flux | ||
| Signed heat transfer rate | ||
| Heat transfer area |
Real-World Applications
Thermal surface loading
Compare average heat flow per unit area.
Boundary conditions
Translate a total heat rate into an average flux.
Worked Example
Problem
A surface of area 0.2 m² transfers 1,000 W in the chosen positive direction. Find its average heat flux.
Given
Solution
Final Answer
Contents
Info
Tools
Source & review
Reference equation: Heat flux. FormuLab wrote new explanations, assumptions, applications, and numerical examples.
Adapted from Teng-Jui Lin, Equation Sheets — Mechanical Engineering Expansion, under CC BY 4.0.
Adapted standard equations and added original lesson text, variables, SI examples, and assumptions.
Assumptions
- • Use the surface area associated with the stated heat transfer rate.
- • For a nonuniform distribution, this is the area-averaged flux.
- • Positive direction must be specified consistently for rate and flux.
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FormuLab is a study reference. Verify formulas, units, assumptions, and course-specific conventions before relying on them.