# Calculate and compare the efficiency of the two turbines of Prob. 14156. They should be the same since we are

## Question:

Calculate and compare the efficiency of the two turbines of Prob. 14–156. They should be the same since we are assuming dynamic similarity. However, the larger turbine will actually be slightly more efficient than the smaller turbine. Use the Moody efficiency correction equation to predict the actual expected efficiency of the new turbine. Discuss.

**Data from Problem 14-156**

Experiments on an existing turbine (A) yield the following data: D_{A} = 86.0 cm, H_{A} =22.0 m,V̇_{A} = 69.5 m^{3}/s, ρ_{A} = 998.0 kg/m^{3}, ṅ_{A} = 240 rpm, bhp_{A} = 11.4 MW. You are to design a new turbine (B) that has the following requirements: ρ_{B} = 998.0 kg/m^{3}, H_{B} = 95.0 m, and ṅ_{B} = 210 rpm. Apply the computer program you developed in Prob. 14–155 to calculate D_{B} (m), V̇_{B} (m^{3}/s), and bhp_{B} (MW). Also calculate the turbine specific speed. What kind of turbine is this (most likely)?

**Data from Problem 14–155**

Develop a general-purpose computer application (using EES or other software) that employs the affinity laws to design a new turbine (B) that is dynamically similar to a given turbine (A). The inputs for turbine A are diameter, net head, capacity, density, rotational speed, and brake horsepower. The inputs for turbine B are density (ρ_{B} may differ from ρ_{A}), available net head, and rotational speed. The outputs for turbine B are diameter, capacity, and brake horsepower. Test your program using the following inputs: D_{A} = 1.40 m, H_{A} = 80.0 m, V̇_{A} = 162 m^{3}/s, ρ_{A} = 998.0 kg/m^{3}, ṅ_{A} = 150 rpm, bhp_{A} = 118 MW, ρ_{B} = 998.0 kg/m^{3}, H_{B} = 95.0 m, and ṅ_{B} = 120 rpm. Verify your results manually.

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**Related Book For**

## Fluid Mechanics Fundamentals And Applications

**ISBN:** 9780073380322

3rd Edition

**Authors:** Yunus Cengel, John Cimbala

**Question Details**

**14**- TURBOMACHINERY

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