Which of the following factors affects the Net Positive Suction Head available (NPSHa) when using a pump?

The Net Positive Suction Head available (NPSHa) is influenced significantly by fluid temperature. As the temperature of the fluid being pumped increases, it can reduce the fluid's density and vapor pressure. An increase in vapor pressure means that the fluid is more likely to vaporize or cavitate under lower pressure conditions. Therefore, a high temperature can lead to decreased NPSHa, which is critical for ensuring that the pump operates efficiently and without cavitation. Maintaining an adequate NPSHa is crucial for pump operation as it reduces the risk of damage and improves performance.

Fluid temperature is specifically relevant because it directly impacts the physical properties of the liquid, such as its vapor pressure, which ultimately affects the suction head available to the pump. Factors like pumping capacity, pump speed, and pipe diameter do have an effect on pumping systems, but they are more related to flow rates and system resistance rather than directly influencing the NPSHa in relation to fluid properties.