Classification check: which is not a reaction turbine? Identify the turbine from the list that is not a reaction type.

Introduction / Context:
Turbines are broadly divided into impulse and reaction types based on how they convert hydraulic energy. Reaction turbines exhibit a pressure drop across the runner passages; impulse turbines rely on high-velocity jets at essentially constant runner pressure. Knowing classic examples prevents misclassification.

Given Data / Assumptions:

• Furneyron and Jonval are early reaction designs (radial- and axial-flow respectively).
• Thomson's (Fourneyron/Thomson variants) are also reaction-type machines.
• Pelton is a pure impulse turbine.

Concept / Approach:
Pelton wheels operate with one or more free jets at atmospheric pressure at the runner; the jet momentum is redirected by buckets to produce torque, with negligible static pressure change through the runner. Therefore, Pelton is not a reaction turbine.

Step-by-Step Solution:
List types: Furneyron (reaction), Jonval (reaction), Thomson's (reaction), Pelton (impulse).Select the non-reaction option: Pelton wheel.

Verification / Alternative check:
Any turbine using a draft tube is reaction; Pelton does not use a draft tube and is installed above tail race, typical of impulse machines.

Why Other Options Are Wrong:
Furneyron, Jonval, and Thomson's all involve pressure changes across the runner and are classic reaction examples; Francis (in option list extension) is also reaction.

Common Pitfalls:
Confusing historical names; assuming only Francis and Kaplan are reaction while older names are impulse.

Final Answer:
Pelton wheel