How To Calculate Condensation Rate

Film Condensation Mass Flow Rate Equation:

\[ \dot{m} = \frac{h A (T_s - T_w)}{h_{fg}} \]

Heat Transfer Coefficient (h):

W/m²K

Surface Area (A):

m²

Surface Temperature (T_s):

°C

Wall Temperature (T_w):

°C

Latent Heat of Vaporization (h_fg):

J/kg

Condensation Mass Flow Rate (ṁ):

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1. What is Film Condensation Mass Flow Rate?

The film condensation mass flow rate equation calculates the rate at which vapor condenses on a surface, forming a continuous liquid film. This is fundamental in heat transfer applications involving phase change, such as in condensers, heat exchangers, and refrigeration systems.

2. How Does the Calculator Work?

The calculator uses the film condensation mass flow rate equation:

\[ \dot{m} = \frac{h A (T_s - T_w)}{h_{fg}} \]

Where:

\( \dot{m} \) — Condensation mass flow rate (kg/s)
\( h \) — Heat transfer coefficient (W/m²K)
\( A \) — Surface area (m²)
\( T_s \) — Saturation temperature of vapor (°C)
\( T_w \) — Wall surface temperature (°C)
\( h_{fg} \) — Latent heat of vaporization (J/kg)

Explanation: The equation relates the heat transfer through condensation to the mass flow rate of the condensate, based on the temperature difference driving the phase change process.

3. Importance of Condensation Rate Calculation

Details: Accurate condensation rate calculation is crucial for designing efficient heat exchangers, optimizing refrigeration cycles, sizing condensers in power plants, and understanding phase change heat transfer in various engineering applications.

4. Using the Calculator

Tips: Enter heat transfer coefficient in W/m²K, surface area in m², temperatures in °C, and latent heat in J/kg. Ensure T_s > T_w for condensation to occur. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is film condensation vs dropwise condensation?
A: Film condensation forms a continuous liquid film on the surface, while dropwise condensation forms discrete droplets. Film condensation is more common in engineering applications.

Q2: How do I determine the heat transfer coefficient?
A: The heat transfer coefficient depends on fluid properties, surface geometry, and flow conditions. It can be calculated using Nusselt number correlations for condensation.

Q3: What affects the latent heat of vaporization?
A: Latent heat varies with pressure and temperature. It decreases as temperature increases and becomes zero at the critical point.

Q4: When is this equation applicable?
A: This equation applies to laminar film condensation on vertical surfaces or horizontal tubes. Modifications are needed for turbulent flow or complex geometries.

Q5: What are typical values for condensation rates?
A: Condensation rates vary widely but typically range from 0.001 to 0.1 kg/s in industrial applications, depending on system size and operating conditions.