Thermal Resistance for Pipe in Square Section Calculator

Thermal Resistance Formula:

\[ R_{th} = \frac{1}{2\pi L} \left( \frac{1}{h_i R} + \frac{L}{k} \ln\left(\frac{1.08a}{2R}\right) + \frac{\pi}{2h_o a} \right) \]

Length (L):

Inside Convection (h_i):

W/m²K

Cylinder Radius (R):

Thermal Conductivity (k):

W/mK

Side of Square (a):

External Convection (h_o):

W/m²K

Thermal Resistance (R_th):

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1. What is Thermal Resistance for Pipe in Square Section?

Thermal resistance for a pipe in square section measures how much the pipe resists heat flow when placed within a square enclosure. It accounts for conduction through the pipe wall and convection on both inside and outside surfaces.

2. How Does the Calculator Work?

The calculator uses the thermal resistance formula:

\[ R_{th} = \frac{1}{2\pi L} \left( \frac{1}{h_i R} + \frac{L}{k} \ln\left(\frac{1.08a}{2R}\right) + \frac{\pi}{2h_o a} \right) \]

Where:

\( R_{th} \) — Thermal resistance (K/W)
\( L \) — Length of pipe (m)
\( h_i \) — Inside convection heat transfer coefficient (W/m²K)
\( R \) — Cylinder radius (m)
\( k \) — Thermal conductivity (W/mK)
\( a \) — Side of square (m)
\( h_o \) — External convection heat transfer coefficient (W/m²K)

Explanation: The formula combines resistance from internal convection, conduction through the pipe wall, and external convection in a square enclosure.

3. Importance of Thermal Resistance Calculation

Details: Accurate thermal resistance calculation is crucial for heat exchanger design, insulation analysis, and thermal management systems in various engineering applications.

4. Using the Calculator

Tips: Enter all values in appropriate SI units. Ensure all inputs are positive values. The calculator provides thermal resistance in Kelvin per Watt (K/W).

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of the 1.08 factor in the formula?
A: The 1.08 factor accounts for the geometric relationship between a circular pipe and its square enclosure in thermal calculations.

Q2: When is this thermal resistance model applicable?
A: This model is suitable for pipes centered in square enclosures with uniform thermal properties and steady-state heat transfer conditions.

Q3: What are typical values for thermal resistance?
A: Thermal resistance values vary widely depending on materials and dimensions, typically ranging from 0.001 to 10 K/W for engineering applications.

Q4: How does pipe length affect thermal resistance?
A: Thermal resistance is inversely proportional to pipe length - longer pipes generally have lower thermal resistance per unit length.

Q5: Can this calculator be used for rectangular enclosures?
A: This specific formula is designed for square enclosures. For rectangular enclosures, different correction factors would be needed.