Hydraulic Characteristics of Channels Quiz
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Questions and Answers

What is the definition of 'two-phase flow'?

  • A mixture of fluid and steam coexisting in a flow, both in gaseous form
  • A mixture of fluid and steam coexisting in a flow, in different forms like bubbles or droplets (correct)
  • A flow where one phase is condensate and the other phase is dry steam
  • A flow where one phase is saturated water and the other phase is superheated steam

    • How are two-phase flows classified based on the character of the mutual phase flow?

  • By the intensity of interaction
  • By the flow pattern (correct)
  • By the relative disposition of phases
  • By the time character of the processes

    • Which type of two-phase flow is characterized by a flow pattern consisting of small, distinct packets of one phase in continuous flow of another phase?

  • Dispersed-annular flow
  • Homogeneous model
  • Dispersed flow
  • Slug flow (correct)

    • In two-phase flows, what does 'non-equilibrium' refer to?

    <p>Flow with phases far from reaching equilibrium</p> Signup and view all the answers

    What distinguishes 'stationary' two-phase flows from 'non-stationary'?

    <p>Stationary flows have constant flow rates, while non-stationary flows have changing rates</p> Signup and view all the answers

    What is the purpose of the Na3PO4 additive in water cleansing?

    <p>To form non-adhesive slag</p> Signup and view all the answers

    Which corrective additives are commonly used in water treatment to suppress oxygen and carbon dioxide?

    <p>Hydrazine and ammonia</p> Signup and view all the answers

    What is the impact of low hardness in feed water on the Water Cleansing Regime (WCR)?

    <p>It allows the realization of WCR without correcting additives</p> Signup and view all the answers

    Which of the following is not a possible solution for water cleansing as mentioned?

    <p>Oxygen oxidation</p> Signup and view all the answers

    How is scaling removal promoted by adding Trilon B to salt-free water?

    <p>By preventing iron oxides deposition</p> Signup and view all the answers

    What determines the allowed thickness of scaling in steam generators?

    <p>Temperature of tube material</p> Signup and view all the answers

    What parameter is represented by Reynolds number ReV and ReL in the context of two-phase flows?

    <p>Velocity</p> Signup and view all the answers

    What does the coefficient X² represent in the context of two-phase flows?

    <p>Unknown parameter</p> Signup and view all the answers

    Which term accounts for drops due to local resistances in two-phase flows?

    <p>Complex Ф² for steam and water</p> Signup and view all the answers

    What is the purpose of the parameter 'ρ′fin, ρ′in' in equation for drops due to acceleration in two-phase flows?

    <p>To represent final and initial values of circulation rate</p> Signup and view all the answers

    What contributes to the static pressure drop in two-phase flows according to the text?

    <p>Sum of scales of the fluid columns for all channel sections</p> Signup and view all the answers

    In two-phase flows, what does the term 'steam quality' x represent in the equation for drops due to acceleration?

    <p>Final and initial steam density</p> Signup and view all the answers

    What is the condition for unambiguous HDC according to the text?

    <p>(∆hin r) * (ρ' ρ'' - 1) ≤ B, where B &gt; 7.5</p> Signup and view all the answers

    What are the consequences of incorrect water chemical regime at NPP SG as per the text?

    <p>All of the above</p> Signup and view all the answers

    What is the main method suggested in the text to fight thermal maldistribution?

    <p>Installing orifices for all inlet regions of the channels</p> Signup and view all the answers

    What does medium subcooling to saturation temperature represent in the context provided?

    <p>Temperature difference from saturation temperature</p> Signup and view all the answers

    Why is resistance of the evaporation zone Δpev dependent on medium flow rate G?

    <p>To achieve unambiguous HDC</p> Signup and view all the answers

    What is the purpose of ensuring a correct water chemical regime at NPP SG?

    <p>To prevent equipment degradation and failure</p> Signup and view all the answers

    What is the main method suggested for preventing tube-to-tube temperature imbalance?

    <p>Installing orifices on all the tubes</p> Signup and view all the answers

    In the context provided, what factor may lead to the transition of some tubes into an impaired heat transfer mode?

    <p>Maldistribution in headers</p> Signup and view all the answers

    What type of calculation adjustments are mentioned in the text?

    <p>t1=var, p2=const</p> Signup and view all the answers

    To prevent thermal maldistribution, what is suggested regarding balancing headers?

    <p>Variable diameter of the tube</p> Signup and view all the answers

    What is recommended as a method for the prevention of tube-to-tube temperature imbalance?

    <p>Installing orifices on all the tubes</p> Signup and view all the answers

    What may happen if the tube wall temperature exceeds a certain permissible temperature in evaporators?

    <p>Transition of some tubes into an impaired heat transfer mode</p> Signup and view all the answers

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