Dynamic pumps and compressors require which of the following?

Dynamic pumps and compressors typically require internal lubrication to ensure smooth operation and to reduce wear and tear on the internal components. Internal lubrication provides a thin film of oil or other lubricants between moving parts, which minimizes friction and prevents overheating. This is essential for maintaining efficiency and longevity of the equipment.

While external cooling, friction bearings, and sealing mechanisms can be important components in some systems, they are not universally required for all dynamic pumps and compressors. External cooling is more relevant in high-performance applications where heat buildup is a concern, but not a fundamental requirement for all. Friction bearings might be used in certain designs but are not a necessity for all dynamic types. Sealing mechanisms are important for preventing fluid leaks, but internal lubrication specifically addresses the operational mechanics of the pump or compressor, making it the core requirement for their proper functioning.