Partial Pressure Of Dry Air Given Vapor Density Calculator

Partial Pressure Of Dry Air Given Vapor Density Formula:

\[ p_a = \frac{\rho_v \times 287 \times t_d}{\omega} \]

Partial Pressure Of Dry Air (pa):

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1. What is Partial Pressure Of Dry Air?

The Partial Pressure of Dry Air is the pressure that is exerted by the dry air in the mixture of dry air and water vapor called moist air. It is an important parameter in thermodynamics and atmospheric science.

2. How Does the Calculator Work?

The calculator uses the Partial Pressure Of Dry Air Given Vapor Density formula:

\[ p_a = \frac{\rho_v \times 287 \times t_d}{\omega} \]

Where:

\( p_a \) — Partial Pressure of Dry Air (Pa)
\( \rho_v \) — Vapor Density (kg/m³)
\( t_d \) — Dry Bulb Temperature (K)
\( \omega \) — Specific Humidity (-)
287 — Gas constant for dry air (J/kg·K)

Explanation: The formula calculates the partial pressure exerted by dry air in a moist air mixture based on vapor density, temperature, and specific humidity.

3. Importance of Partial Pressure Calculation

Details: Calculating partial pressure of dry air is crucial for understanding atmospheric conditions, HVAC system design, and various industrial processes involving air-water vapor mixtures.

4. Using the Calculator

Tips: Enter vapor density in kg/m³, dry bulb temperature in Kelvin, and specific humidity (dimensionless). All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between partial pressure and total pressure?
A: Partial pressure is the pressure exerted by a single gas component in a mixture, while total pressure is the sum of all partial pressures in the mixture.

Q2: Why is the gas constant 287 used in this formula?
A: 287 J/kg·K is the specific gas constant for dry air, derived from the universal gas constant divided by the molar mass of dry air.

Q3: How does temperature affect partial pressure of dry air?
A: Partial pressure of dry air increases with temperature, as the gas molecules move faster and exert more pressure on container walls.

Q4: What are typical values for partial pressure of dry air?
A: At standard atmospheric conditions, partial pressure of dry air is approximately 78-79 kPa out of the total 101.325 kPa.

Q5: Can this formula be used for other gas mixtures?
A: This specific formula is designed for dry air in air-water vapor mixtures. Other gas mixtures require different calculations based on their specific properties.