Examkin

Question

Difficulty: HardParaphrased Fact Recognition

In high-flow industrial pumping systems, cavitation occurs when the local liquid pressure drops below the fluid's vapor pressure at the pump suction eye, forming transient vapor bubbles. As these vapor cavities travel downstream into regions of higher hydrostatic pressure inside the impeller vanes, they collapse violently. The microscopic shockwaves and localized micro-jets produced during this collapse exceed the yield strength of the impeller alloy, causing severe pitting and structural fatigue. To mitigate this destructive erosion without decreasing pump throughput, plant operators must elevate the net positive suction head available (NPSHANPSH_A) by either increasing the suction vessel liquid level or cooling the incoming fluid to suppress its vapor pressure.

Based on the passage, which of the following actions will help prevent cavitation erosion while maintaining full operational flow?

  1. A
    Decreasing pump throughput to keep local liquid pressure from falling at the suction eye
  2. Lowering the temperature of the entering liquid to reduce the tendency of vapor formationAnswer
  3. C
    Directing vapor bubbles into lower hydrostatic pressure zones to elevate the yield strength of the impeller alloy
  4. D
    Applying a sacrificial elastomer lining to the interior casing to absorb mechanical vibrations

Answer

Lowering the temperature of the entering liquid to reduce the tendency of vapor formation
The correct response accurately restates the author's statement that operators can prevent cavitation while preserving throughput by 'cooling the incoming fluid to suppress its vapor pressure.' 'Lowering the temperature of the entering liquid' is a direct synonym for 'cooling the incoming fluid,' and 'reduce the tendency of vapor formation' accurately captures 'suppress its vapor pressure.'

Step-by-Step Solution

1
Identify the target condition and constraint in the question stem
The goal is to identify a method mentioned in the text that prevents cavitation damage without diminishing pump flow rate.
The prompt specifies maintaining operational throughput while mitigating erosion.
2
Locate the relevant factual detail within the passage
The final sentence states that operators can elevate NPSHANPSH_A 'without decreasing pump throughput, ... by either increasing the suction vessel liquid level or cooling the incoming fluid to suppress its vapor pressure.'
This sentence provides the exact procedural solutions aligned with the prompt's constraints.
3
Map the identified factual detail to its synonymously paraphrased equivalent
'Cooling the incoming fluid to suppress its vapor pressure' corresponds directly to 'lowering the temperature of the entering liquid to reduce the tendency of vapor formation.'
Paraphrased fact recognition requires validating semantic equivalence across restructured syntax and vocabulary.

Key Concept

Paraphrased Fact Recognition
Estimated Time:1m 15s
Rate this question

Topics

Paraphrased Fact Recognition

More questions from this topic