Calculation — Thermowell Wake Frequency

(simplified uniform beam): ( I = \frac\pi (d_root^4 - d_bore^4)64 ) (assume bore dia 6 mm → 0.006 m) ( I ≈ 8.9 × 10^-8 , m^4 ) ( m_metal = \rho_m × \textcross-sectional area ≈ 8000 × 7.85e-4 = 6.28 , kg/m ) ( m_added = 1000 × 4.91e-4 = 0.49 , kg/m ) ( m_total = 6.77 , kg/m )

[ f_n = \frac\lambda^22\pi L^2 \sqrt\fracEIm ] thermowell wake frequency calculation

1. Introduction A thermowell is a pressure-tight receptacle inserted into a process pipe or vessel to protect a temperature sensor (e.g., RTD, thermocouple) from corrosive, high-pressure, or high-velocity fluids. When fluid flows past a thermowell, alternating vortices shed from its downstream side—a phenomenon known as vortex shedding or a Kármán vortex street . (simplified uniform beam): ( I = \frac\pi (d_root^4

[ St = \fracf_w \cdot dV ]