# What is the formula for thermal diffusivity?

## What is the formula for thermal diffusivity?

Thermal diffusivity is the rate of transfer of heat of a material from the hot side to the cold side – a measure of how quickly a material can absorb heat from its surroundings. It can be calculated by taking the thermal conductivity divided by density and specific heat capacity at constant pressure.

## What is Rho CP?

Transcribed image text: where (rho cp) is the volumetric heat capacity, K is the thermal conductivity and S is a source/sink term. Recall that the earth is spherical and assume the dominant transport of heat occurs in the radial direction only.

What is K in Prandtl number?

The Prandtl number (Pr = ν / α) is defined as the dimensionless ratio between kinematic viscosity (ν) and thermal diffusivity, α = k / (ρ·cp); where k stands for thermal conductivity, ρ stands for density, and cp is the (isobaric) specific heat capacity.

### What is Rho in heat transfer?

ρ is density (kg/m³) cp is specific heat capacity (J/(kg·K))

### What is the term α in equation α k /( ΡCP?

The thermal diffusivity can be expressed in terms of the thermal conductivity, the density and the specific heat as α=k/(ρcp).

How do you write a heat equation?

Heat energy = cmu, where m is the body mass, u is the temperature, c is the specific heat, units [c] = L2T−2U−1 (basic units are M mass, L length, T time, U temperature). c is the energy required to raise a unit mass of the substance 1 unit in temperature.

## What is CP in heat transfer?

The specific heat capacity Cp [kJ/kg/°C] is a thermodynamic property specific of the fluid used to transfer heat. The specific heat capacity of water does vary with temperature but for the scope of a hot water loop it is essentially constant.

## How do I find out my PR number?

The Pr number (Pr = Cpμ/k) is calculated from Eq. (8.17) and only depends on the properties of the fluid. At a given T and P, the thermodynamic state of the fluid is fixed.

What do you mean by Sherwood number?

Sherwood number represents the ratio between mass transfer by convection (β) and mass transfer by diffusion (δ/L). It is the mass transfer equivalent of Nusselt Number, Nu, and is a function of Reynolds Number, Re, and Schmidt Number, Sc.

### What is Rho thermal resistivity?

Thermal resistivity, or Rho, is defined in the National Electrical Code (2014) as “the heat transfer capability through a substance by conduction.” It is the reciprocal of thermal conductivity. Thermal resistivity is often reported in different measurement units.