1. What is Falling Rate Drying Time?

Definition: This calculator determines the falling rate drying time based on total drying time and constant rate drying time.

Purpose: It helps in drying process analysis by separating the falling rate period from the total drying time.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( t_f \) — Falling rate drying time (seconds)
• \( t \) — Total drying time (seconds)
• \( t_c \) — Constant rate drying time (seconds)

Explanation: The falling rate period is calculated by subtracting the constant rate period from the total drying time.

3. Importance of Falling Rate Drying Time

Details: Understanding the falling rate period helps in optimizing drying processes, energy consumption, and product quality control.

4. Using the Calculator

Tips: Enter the total drying time and constant rate drying time in seconds. Both values must be > 0 and total time must be ≥ constant rate time.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between constant and falling rate periods?
A: Constant rate period has steady evaporation from surface, while falling rate period has decreasing evaporation as moisture moves internally.

Q2: Why is falling rate drying time important?
A: It often determines the overall drying time and affects product quality and energy efficiency.

Q3: Can falling rate time be longer than constant rate time?
A: Yes, for many materials the falling rate period is significantly longer than the constant rate period.

Q4: How do I measure constant rate drying time?
A: It's typically the initial period where drying rate remains constant, often determined experimentally.

Q5: What factors affect falling rate drying time?
A: Material properties, thickness, temperature, humidity, and air velocity all influence falling rate drying.