Partial Pressure Of Water Vapor At Wet Bulb Temperature Calculator

Formula Used:

\[ P_w = \frac{h_{conv} \times (T_{\infty} - T_w)}{h_{fg} \times k_L} + P_{\infty} \]

Convective Heat Transfer Coefficient:

W/m²K

Air Temperature:

°C

Wet Bulb Temperature:

°C

Enthalpy of Evaporation:

J/kg·K

Convective Mass Transfer Coefficient:

m/s

Partial Pressure in Air:

Partial Pressure Of Water Vapor At Wet Bulb Temperature:

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1. What is Partial Pressure Of Water Vapor At Wet Bulb Temperature?

Partial pressure of water vapor at wet bulb temperature is a key parameter in psychrometrics and heat transfer calculations. It represents the pressure exerted by water vapor in a mixture of air and water vapor when the air is saturated at the wet bulb temperature.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_w = \frac{h_{conv} \times (T_{\infty} - T_w)}{h_{fg} \times k_L} + P_{\infty} \]

Where:

\( P_w \) — Partial pressure of water vapor at wet bulb temperature (Pa)
\( h_{conv} \) — Convective heat transfer coefficient (W/m²K)
\( T_{\infty} \) — Air temperature (°C)
\( T_w \) — Wet bulb temperature (°C)
\( h_{fg} \) — Enthalpy of evaporation (J/kg·K)
\( k_L \) — Convective mass transfer coefficient (m/s)
\( P_{\infty} \) — Partial pressure in air of water vapor (Pa)

Explanation: This formula calculates the partial pressure of water vapor at the wet bulb temperature based on heat and mass transfer principles.

3. Importance of Partial Pressure Calculation

Details: Accurate calculation of partial pressure at wet bulb temperature is crucial for HVAC system design, psychrometric chart analysis, and understanding evaporation processes in various engineering applications.

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Ensure temperature values are in Celsius, heat transfer coefficients in W/m²K, enthalpy in J/kg·K, mass transfer coefficient in m/s, and pressure in Pa.

5. Frequently Asked Questions (FAQ)

Q1: What is the significance of wet bulb temperature?
A: Wet bulb temperature represents the lowest temperature that can be reached by evaporative cooling and is important for understanding humidity and heat transfer processes.

Q2: How does convective heat transfer affect partial pressure?
A: Higher convective heat transfer increases the rate of evaporation, which affects the partial pressure calculation at the wet bulb temperature.

Q3: What are typical values for enthalpy of evaporation?
A: For water at standard conditions, the enthalpy of evaporation is approximately 2257 kJ/kg, but it varies with temperature.

Q4: When is this calculation most useful?
A: This calculation is particularly useful in HVAC design, drying processes, and any application involving evaporative cooling or humidification.

Q5: Are there limitations to this formula?
A: The formula assumes ideal conditions and may need adjustments for extreme temperatures, pressures, or non-standard atmospheric conditions.