Shell-Side Pressure Drop Calculator
Estimate shell-side pressure drop in shell-and-tube heat exchangers using the Kern method. Essential for exchanger rating and hydraulic verification.
Accurate prediction of shell-side pressure drop is critical for heat exchanger rating and piping system design. This calculator utilizes the standard Kern method correlations to estimate crossflow area, mass velocity, Reynolds number, and final pressure drop based on your exchanger geometry and fluid properties.
Exchanger Geometry
Fluid Properties
Formulas Used (Kern Method)
1. Crossflow Area:
\[ a_s = \frac{D_s \times C' \times B}{P_T \times 144} \quad \text{[ft²]} \]
Where Clearance \( C' = P_T - OD \)
2. Mass Velocity & Reynolds Number:
\[ G_s = \frac{W}{a_s} \quad \text{[lb/hr·ft²]} \]
\[ Re = \frac{D_e \times G_s}{\mu \times 2.419} \]
3. Shell-Side Pressure Drop:
\[ \Delta P_s = \frac{f \cdot G_s^2 \cdot D_s \cdot (N+1)}{5.22 \times 10^{10} \cdot D_e \cdot s} \quad \text{[psi]} \]
Understanding Shell-Side Pressure Drop
The shell-side pressure drop in a baffled shell-and-tube heat exchanger is primarily composed of the pressure drop across the tube bundle in crossflow and the pressure drop in the baffle windows. The Kern method provides a simplified, conservative estimate that is widely used for preliminary exchanger rating.
Key Assumptions & Limitations
- The Kern method assumes ideal crossflow and does not explicitly account for leakage streams (tube-to-baffle or shell-to-baffle) or bypass streams, which can significantly reduce the actual pressure drop.
- For highly accurate predictions, especially in fixed-tubesheet or low-Reynolds-number services, the Bell-Delaware method is recommended.
- The friction factor \( f \) is highly dependent on the Reynolds number and tube layout (triangular vs. square). If left blank, the calculator uses the empirical correlation \( f = \exp(0.576 - 0.19 \ln(Re)) \).