From c90147635a24b4fd4dcc7079f0e183c016b4f0bd Mon Sep 17 00:00:00 2001 From: Alvie Rahman Date: Mon, 8 May 2023 17:29:40 +0100 Subject: [PATCH] explain variable in nusselt number --- .../2047_thermodynamics_and_fluid_dynamics/heat_transfer.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/uni/mmme/2047_thermodynamics_and_fluid_dynamics/heat_transfer.md b/uni/mmme/2047_thermodynamics_and_fluid_dynamics/heat_transfer.md index 4501548..16bda4d 100755 --- a/uni/mmme/2047_thermodynamics_and_fluid_dynamics/heat_transfer.md +++ b/uni/mmme/2047_thermodynamics_and_fluid_dynamics/heat_transfer.md @@ -72,11 +72,12 @@ Nusselt number is a dimensionless number: $$\text{Nu} = \frac{hL}{k_f}$$ where $k_f$ is conductivity of the fluid, $L$ is the representative length (e.g. diameter, length, -internal width, etc.). +internal width, etc.), and $h$ is heat transfer coefficient. Since $h$ is unknown a lot of the time, sometimes Nusselt number must be found through approximating by other dimensionless numbers: Prandtl, Reynolds, and Grashof. + Nusselt number for a laminar forced flow is around 3.66. For a turbulent forced flow it is estimated to be: