Heat Transfer Coefficient Calculator

Calculate convective heat transfer coefficients for various configurations

Forced Convection

Calculate convective heat transfer for forced flow configurations

Flow Type

Fluid Velocity (m/s)

Characteristic Length (m) Diameter for pipes, length for plates

Fluid Viscosity (cP)

Fluid Density (kg/m³)

Fluid Conductivity (W/m·K)

Fluid Specific Heat (kJ/kg·K)

Natural Convection

Calculate convective heat transfer for natural convection scenarios

Geometry

Characteristic Length (m) Height for vertical surfaces, diameter for cylinders

Surface Temperature (°C)

Fluid Temperature (°C)

Fluid Viscosity (cP)

Fluid Density (kg/m³)

Fluid Conductivity (W/m·K)

Fluid Specific Heat (kJ/kg·K)

Thermal Expansion Coeff. (1/K)

Heat Exchanger Design

Calculate overall heat transfer coefficients for exchanger configurations

Exchanger Type

Tube Diameter (mm)

Tube Side Velocity (m/s)

Shell Side Velocity (m/s)

Tube Side Fluid

Shell Side Fluid

Tube Inlet Temp (°C)

Tube Outlet Temp (°C)

Shell Inlet Temp (°C)

Shell Outlet Temp (°C)

Calculation Results

Convective Heat Transfer Coefficient

W/m²·K

Nusselt Number

Reynolds Number

Prandtl Number

Flow Regime

Convective Heat Transfer Coefficient

W/m²·K

Nusselt Number

Grashof Number

Prandtl Number

Rayleigh Number

Heat Transfer Coefficient Fundamentals

Forced Convection

Forced convection heat transfer is calculated using correlations of the form: Nu = C·Re^m·Prⁿ where Nu is Nusselt number (hL/k), Re is Reynolds number (ρvL/μ), and Pr is Prandtl number (C_pμ/k). The constants C, m, n depend on the flow geometry and regime (laminar/turbulent).

Nu = C·Re^m·Prⁿ

Natural Convection

Natural convection depends on the Grashof number (Gr = gβΔTL³/ν²) which represents the ratio of buoyancy to viscous forces. The Rayleigh number (Ra = Gr·Pr) determines the flow regime. Common correlations are: Nu = C·Raⁿ where C and n depend on geometry and Ra range.

Nu = C·Raⁿ

Heat Exchanger Design

The overall heat transfer coefficient (U) combines resistances: 1/U = 1/h_i + R_fouling + R_wall + 1/h_o where h_i and h_o are inside and outside coefficients. The log mean temperature difference (LMTD) is: ΔT_lm = (ΔT₁-ΔT₂)/ln(ΔT₁/ΔT₂) for counter-current flow.

1/U = 1/h_i + R_fouling + R_wall + 1/h_o