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Chapter 8 • Theory & Derivations

Performance Testing, Controls and Sustainable Operations

Comprehensive university textbook unit covering fundamental principles, governing relationships, and engineering applications of Performance Testing, Controls and Sustainable Operations.

§8.1 Design and off-design performance maps

**Outcome.** Use conservation laws and appropriate reference stations to analyze **design and off-design performance maps**; solve a traceable numerical example; expose model limitations; and justify a provisional engineering choice. This is Unit 08, **Performance Testing, Controls and Sustainable Operations**.

§8.2 Instrumentation and propagated uncertainty

**Outcome.** Use conservation laws and appropriate reference stations to analyze **instrumentation and propagated uncertainty**; solve a traceable numerical example; expose model limitations; and justify a provisional engineering choice. This is Unit 08, **Performance Testing, Controls and Sustainable Operations**.

§8.3 Control loops and actuator constraints

**Outcome.** Use conservation laws and appropriate reference stations to analyze **control loops and actuator constraints**; solve a traceable numerical example; expose model limitations; and justify a provisional engineering choice. This is Unit 08, **Performance Testing, Controls and Sustainable Operations**.

§8.4 Condition monitoring and degradation diagnosis

**Outcome.** Use conservation laws and appropriate reference stations to analyze **condition monitoring and degradation diagnosis**; solve a traceable numerical example; expose model limitations; and justify a provisional engineering choice. This is Unit 08, **Performance Testing, Controls and Sustainable Operations**.

§8.5 Lifecycle assessment and integrated design review

**Outcome.** Use conservation laws and appropriate reference stations to analyze **lifecycle assessment and integrated design review**; solve a traceable numerical example; expose model limitations; and justify a provisional engineering choice. This is Unit 08, **Performance Testing, Controls and Sustainable Operations**.

THREE WORKED QUESTIONS

Step-by-Step Turbomachinery Solutions

Three original questions connect calculations, definitions and interpretation. Open each solution to follow the reasoning.

Solved Problem Example 8.1: Calculation & Verification: Design and off-design performance maps

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Design and off-design performance maps** under steady operational loading.

Worked Engineering Derivation:

**Teaching case:** A pump at 32 kW hydraulic and 43 kW shaft power operates at eta≈0.744. **Explicit substitution:** eta=32/43; therefore **0.7442**. Hydraulic or aerodynamic power and shaft power must share a time boundary. Check arithmetic independently. Then perturb one input by 10%: linear, quadratic and cubic factors become 1.1, 1.21 and 1.331, respectively. Recompute nonlinear property relationships. An algebraic change is not evidence of a new real-machine operating point.

Solved Problem Example 8.2: Calculation & Verification: Instrumentation and propagated uncertainty

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Instrumentation and propagated uncertainty** under steady operational loading.

Worked Engineering Derivation:

**Teaching case:** A product with 2% independent flow error and 1% head error has ≈2.24% relative standard uncertainty. **Explicit substitution:** u_rel=sqrt(2²+1²); therefore **2.236%**. The root-sum-square is justified only if the errors are independent. Check arithmetic independently. Then perturb one input by 10%: linear, quadratic and cubic factors become 1.1, 1.21 and 1.331, respectively. Recompute nonlinear property relationships. An algebraic change is not evidence of a new real-machine operating point.

Solved Problem Example 8.3: Calculation & Verification: Control loops and actuator constraints

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Control loops and actuator constraints** under steady operational loading.

Worked Engineering Derivation:

**Teaching case:** A proportional controller with gain 0.15 per kPa sees 10 kPa error and requests a 1.5 unit actuator correction before saturation. **Explicit substitution:** Delta u=Kp e=0.15×10; therefore **1.5 actuator units**. Saturation and derivative control are not included in this illustrative P action. Check arithmetic independently. Then perturb one input by 10%: linear, quadratic and cubic factors become 1.1, 1.21 and 1.331, respectively. Recompute nonlinear property relationships. An algebraic change is not evidence of a new real-machine operating point.

Solved Problem Example 8.4: Calculation & Verification: Condition monitoring and degradation diagnosis

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Condition monitoring and degradation diagnosis** under steady operational loading.

Worked Engineering Derivation:

**Teaching case:** Efficiency falling from 0.84 to 0.80 at matched conditions corresponds to 4 percentage points, not 4% relative. **Explicit substitution:** eta_ref−eta_now=0.84−0.80; therefore **0.04 = 4 percentage points**. Relative decrease is 0.04/0.84≈4.76%, a different statistic. Check arithmetic independently. Then perturb one input by 10%: linear, quadratic and cubic factors become 1.1, 1.21 and 1.331, respectively. Recompute nonlinear property relationships. An algebraic change is not evidence of a new real-machine operating point.

Solved Problem Example 8.5: Calculation & Verification: Lifecycle assessment and integrated design review

Problem Statement: An engineering practitioner analyzes a mechanical system governed by **Lifecycle assessment and integrated design review** under steady operational loading.

Worked Engineering Derivation:

**Teaching case:** A 12 kW mean auxiliary load running 5000 h/y uses 60 MWh/y; at $0.12/kWh its electricity cost is $7200/y. **Explicit substitution:** E=12 kW×5000 h=60,000 kWh; cost=60,000×0.12; therefore **60 MWh and USD 7200 per year**. No discounted cash flow or maintenance cost is included. Check arithmetic independently. Then perturb one input by 10%: linear, quadratic and cubic factors become 1.1, 1.21 and 1.331, respectively. Recompute nonlinear property relationships. An algebraic change is not evidence of a new real-machine operating point.