Final answer:
The migration of refrigerant to the compressor's crank case is due to differences in solubility and vapor pressure between the oil and refrigerant. This is important for the proper operation of refrigeration systems and requires specific designs to manage these differences.
Step-by-step explanation:
The migration of refrigerant to a compressor's crank case is typically because of a difference in solubility and vapor pressure between the oil and refrigerant at various temperatures. During the off cycle of a refrigeration system, the refrigerant, which has a higher vapor pressure compared to the oil, can migrate towards the oil in the compressor's crank case. This phenomenon is particularly problematic if the compressor starts while there is liquid refrigerant in the crankcase, which can lead to 'refrigerant slugging' and potential compressor damage. To prevent this, systems are designed with various controls and heaters to maintain appropriate pressure differences and to ensure the refrigerant stays in the proper phase.
Understanding the significance of solubility and vapor pressure is crucial for the efficient operation of cooling systems, as these properties dictate the behavior and movement of refrigerants within the system. The Temperature Curves and Check Your Learning sections highlight how compression and temperature affect the state of various gases, relevant to the operation of heat pumps and refrigerators. The LibreTexts snippet underscores the importance of viscosity in lubricants and their performance under different temperature conditions, which links back to the behavior of refrigerants in a system.