Centrifugal pumps and positive displacement pumps operate on different principles. Centrifugal pumps use centrifugal force to accelerate fluid, increasing its kinetic energy, which is then converted into pressure energy. In contrast, positive displacement pumps use a mechanical seal or diaphragm to displace a fixed volume of fluid, resulting in a constant flow rate. Positive displacement pumps are better suited for applications requiring high pressure and low flow rates, while centrifugal pumps are ideal for high-flow, low-pressure applications.