Relationship between air compressor exhaust volume and discharged compressed air volume
The exhaust volume of air compressor and the amount of compressed air discharged are two closely related concepts with different meanings. The relationship needs to be analyzed from three aspects: definition, calculation method and influencing factors:
1. Comparison of core definitions
| indicators | exhaust volume | Volume of compressed air discharged |
|---|---|---|
| physical meaning | Volume of gas inhaled and compressed per unit of time (converted into inhaled state) | Actual output volume of compressed gas per unit time (standard state) |
| measurement benchmark | Inhalation state (normal pressure, normal temperature) | Standard state (0.1MPa, 0℃) |
| industry term | Volume flow (m³/min) | Gas supply volume (m³/min) |
2. Derivation of mathematical relationships
According to the ideal gas equation of state:
A conversion formula for the two can be derived:
Among them:
- : Amount of compressed air discharged
- : Exhaust volume
- : Pressure,: Temperature
- standard state：
simplified example：
When displacement , exhaust pressure , exhaust temperature (50℃):
3. Key influencing factors
- compression ratio：
- compression ratio The greater the compression ratio, the less the amount of compressed air discharged.
- typical data: When the compression ratio is increased from 3 to 5, the gas supply volume drops by about 18%.
- temperature coefficient：
- For every 10℃ increase in exhaust temperature, the supply air volume decreases by about 3%.
- solutions: The use of multi-stage compression or intercooler can significantly increase the air supply.
- leakage loss：
- For every 0.1mm increase in piston ring/rotor clearance, the air supply volume decreases by 5 – 8%.
- improvement measures: Use precision machining or coating technology to reduce leaks.
- clearance volume：
- For every 5% increase in the proportion of clearance volume, the gas supply volume will decrease by 2 – 3%.
- optimization design: Reduce the impact of clearance by reducing the piston/rotor diameter ratio.
4. Analysis of practical application scenarios
| working conditions | Relationship between exhaust volume vs. supply volume | Equipment selection suggestions |
|---|---|---|
| Normal temperature and low pressure (≤0.5MPa) | Gas supply ≈ exhaust volume × 0.85 | Available according to 1:1 ratio |
| High temperature and high pressure (≥1MPa) | Gas supply ≈ exhaust volume × 0.6 | 20-30% margin needs to be reserved |
| frequency conversion adjustment | The gas supply volume changes linearly with the frequency, and the exhaust volume declines exponentially. | Recommended to match a gas storage tank (capacity ≥15% displacement) |
| intermittent gas use | Gas supply volume fluctuation> Exhaust volume fluctuation | Recommended configuration of dryer + filter combination |
5. Energy efficiency optimization strategy
- compression ratio matching：
- The compression stage is designed according to the demand of the gas end, and the single-stage compression ratio is recommended to be controlled within 4.
- waste heat recovery：
- Use exhaust heat to preheat intake air, improving energy efficiency by 3-5%.
- intelligent control：
- Monitor the gas supply volume through the Internet of Things, dynamically adjust the exhaust volume, and save energy by 10-15%.
conclusion: The exhaust volume of the air compressor is the theoretical production capacity indicator, while the discharged compressed air volume is the actual effective output. The two are related through a state equation. In actual selection, correction calculations need to be made based on parameters such as pressure, temperature, and leakage. It is recommended to reserve a safety margin of 15-20% to ensure stable operation of the system.