Final Answer:
The pressure drop that occurs across both the moving and fixed blades of a reaction turbine is the result of the change in momentum of the fluid passing through the blades.
Step-by-step explanation:
In a reaction turbine, the pressure drop across the moving and fixed blades is fundamentally due to the change in momentum of the fluid passing through these components. When the fluid enters the turbine, it possesses kinetic energy due to its velocity. As the fluid flows through the fixed blades, it experiences a change in direction. According to Newton's second law of motion, this change in momentum results in a force being exerted on the fluid, causing a pressure drop across the fixed blades.
The pressure drop across the moving blades occurs as the fluid further changes direction and velocity. The moving blades accelerate the fluid, causing it to transfer more momentum to the blades and hence experience an additional pressure drop. This change in momentum of the fluid as it passes through both the moving and fixed blades ultimately leads to a drop in pressure.
Mathematically, the change in momentum can be expressed as ΔP = Δ(mv), where ΔP is the change in pressure, m is the mass flow rate of the fluid, and v is the velocity of the fluid. However, the detailed calculation involving the change in momentum for a specific turbine would require knowledge of the turbine's design parameters, fluid properties, and operating conditions. Overall, the pressure drop across the moving and fixed blades of a reaction turbine is a result of the change in momentum experienced by the fluid as it passes through these components.