Pelton wheel — classify by flow type and action Identify the correct classification of a Pelton turbine based on the nature of flow and energy conversion.

Introduction:
Pelton wheels are classic high-head turbines. Understanding whether they are impulse or reaction type, and the direction of flow relative to the runner, is fundamental for selection and design in hydroelectric systems.

Given Data / Assumptions:

• Water issued from one or more nozzles strikes spoon-shaped buckets.
• Jet is at atmospheric pressure at impact; pressure changes across blades are negligible.
• Flow is primarily tangential to the runner periphery.

Concept / Approach:
Impulse turbines convert the entire pressure head into jet kinetic energy before the runner. The runner then extracts energy by deflecting the jet, ideally with negligible pressure change across the buckets. Directionally, the Pelton jet strikes tangentially at the bucket splitter and is reversed to maximize momentum change and torque.

Step-by-Step Solution:

Verification / Alternative check:
Reaction turbines (Francis, Kaplan) operate with pressure change within runner passages; Pelton does not. Radial-inflow impulse types are historical (e.g., Turgo uses oblique jet) but Pelton specifically uses tangential jets.

Why Other Options Are Wrong:

• Inward/outward flow impulse: not the standard Pelton configuration.
• Inward/axial flow reaction: imply pressure change across runner, which is not the Pelton principle.

Common Pitfalls:
Confusing Pelton (impulse) with Francis/Kaplan (reaction); assuming “tangential” means axial—tangential is along the periphery, not the axis.

Final Answer: