If the viscosity of the liquid being...

🔍 Key Concepts

• Rotary pump characteristics – how flow (capacity) behaves when discharge pressure changes at constant viscosity • Difference between positive displacement pumps (like most rotary pumps) and centrifugal pumps • Relationship between suction conditions and discharge pressure in a closed piping system

💭 Think About

• Ask yourself: on a positive displacement rotary pump, does the flow rate depend mainly on pressure, or on the pump’s geometry and speed (rpm)? • If the discharge side gets harder to push against (higher pressure), what typically happens first: the pump slips internally, the capacity changes a lot, or system components (like relief valves) react? • Which of the four options is directly tied to what changes at the suction side, and which are about what happens at the discharge side when back pressure rises?

✅ Before You Answer

• Verify whether a rotary pump is considered a positive displacement pump and what that implies for nearly constant flow at varying discharge pressures (assuming no slip). • Check if an increase in discharge pressure automatically causes a change in suction pressure, or if suction pressure mainly depends on NPSH (net positive suction head), suction lift, and supply tank conditions. • Confirm whether, for exam purposes, capacity of a rotary pump is treated as essentially constant with pressure changes when viscosity and speed are constant.

If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump __________.

capacity will increase

capacity will decrease

suction pressure will increase

suction pressure will decrease

🔍 Key Concepts

💭 Think About

✅ Before You Answer