Enthalpy Of Wall Using Stanton Number Calculator

Formula Used:

\[ h_w = h_{aw} - \frac{q_w}{\rho_e \cdot u_e \cdot St} \]

Adiabatic Wall Enthalpy (h_aw):

J/kg

Local Heat Transfer Rate (q_w):

W/m²

Static Density (ρ_e):

kg/m³

Static Velocity (u_e):

m/s

Stanton Number (St):

Wall Enthalpy (h_w):

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1. What is Wall Enthalpy?

Wall Enthalpy is the Enthalpy of a fluid flowing around a solid body; it corresponds to the adiabatic wall temperature. It's an important parameter in heat transfer calculations for fluid dynamics and thermal engineering applications.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ h_w = h_{aw} - \frac{q_w}{\rho_e \cdot u_e \cdot St} \]

Where:

\( h_w \) — Wall Enthalpy (J/kg)
\( h_{aw} \) — Adiabatic Wall Enthalpy (J/kg)
\( q_w \) — Local Heat Transfer Rate (W/m²)
\( \rho_e \) — Static Density (kg/m³)
\( u_e \) — Static Velocity (m/s)
\( St \) — Stanton Number (dimensionless)

Explanation: This formula calculates the wall enthalpy by subtracting the heat transfer component from the adiabatic wall enthalpy, considering fluid properties and heat transfer characteristics.

3. Importance of Wall Enthalpy Calculation

Details: Accurate wall enthalpy calculation is crucial for thermal analysis in aerospace engineering, heat exchanger design, and any application involving heat transfer between fluids and solid surfaces. It helps in determining thermal loads and designing appropriate cooling systems.

4. Using the Calculator

Tips: Enter all values in appropriate units. Adiabatic wall enthalpy and wall enthalpy are in J/kg, heat transfer rate in W/m², density in kg/m³, velocity in m/s, and Stanton number is dimensionless. All values must be positive, with density and velocity greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the Stanton Number?
A: The Stanton Number is a dimensionless number that measures the ratio of heat transferred into a fluid to the thermal capacity of the fluid.

Q2: When is this calculation particularly important?
A: This calculation is particularly important in high-speed flow applications, turbine blade cooling, and any scenario where accurate thermal boundary conditions are needed.

Q3: What are typical values for Stanton Number?
A: Stanton Number typically ranges from 0.001 to 0.01 for most engineering applications, depending on flow conditions and surface characteristics.

Q4: How does wall enthalpy relate to temperature?
A: For ideal gases, enthalpy is directly related to temperature through the specific heat capacity (h = c_pT), so wall enthalpy can be converted to wall temperature if the specific heat is known.

Q5: What are the limitations of this formula?
A: This formula assumes constant fluid properties and may need modification for compressible flows, chemical reactions, or cases with significant property variations across the boundary layer.