Thermowell Wake Frequency Calculation -

determines the vortex shedding frequency and compares it to the thermowell’s natural frequency to ensure safe operation. 2. Governing Physics 2.1 Strouhal Number (St) The dimensionless Strouhal number relates vortex shedding frequency to flow velocity and thermowell diameter:

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

If the frequency of these vortices coincides with the natural frequency of the thermowell, occurs. This can cause large-amplitude vibrations, leading to fatigue failure, fracture, and loss of process containment. determines the vortex shedding frequency and compares it

(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 ) When fluid flows past a thermowell, alternating vortices

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 .

[ St = \fracf_w \cdot dV ]