Final answer:
To calculate the mass flow of the refrigerant R-22, you compute the volume displaced by the compressor based on its dimensions and RPM, then multiply by the refrigerant's density at the specified temperature.
Step-by-step explanation:
To calculate the mass flow of the refrigerant R-22 per minute using a four-cylinder single stage compressor with a 100 mm bore and a 120 mm stroke operating at 400 RPM, we need to consider several steps. First, we calculate the total volume displaced by the compressor in one cycle. Then, we consider the operating conditions, specifically the evaporator temperature at -15°C, to determine the refrigerant's density. The product of the volume displaced per minute and the refrigerant's density gives the mass flow rate.
The formula for the volume displaced by one cylinder in one cycle (stroke) is:
V = π × (Bore/2)^2 × Stroke
Where:
- V is the volume in cubic meters,
- Bore is the diameter of the cylinder,
- Stroke is the length of the piston's movement.
Once we compute the volume per cylinder, we multiply by the number of cylinders and the RPM to find the total volume per minute. Note that RPM must be converted to cycles per minute for a four-stroke engine, which means dividing by two since a cycle is completed every two revolutions. Afterwards, we need to look up the density of refrigerant R-22 at -15°C to finalize the mass flow rate. The given options do not directly provide a clear method for determining the correct answer, as additional information such as specific volumetric efficiency and refrigerant's density at the given condition are essential components needed for the final calculation. Nevertheless, the method outlined here is the correct approach to solve such a problem.