what is the factor where the loss coefficients depend on line___?
Answers
Answer: The local loss coefficient also has a similar effect as in two-phase natural circulation loops (see Fig. 6.13). The subcritical loss coefficient or the loss coefficient at the heater inlet has a significant influence in reducing the natural circulation flow rate. The influence of the loss coefficient in the supercritical region (or the heater outlet) is significantly greater than that of the loss coefficient in the subcritical region. This behavior is similar to two-phase loops where the loss coefficient in the two-phase region has a far greater influence on the flow rate than the loss coefficient in the single-phase region.
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Figure 6.13. Effect of loss coefficient on the supercritical natural circulation flow rate.
Governing differential equations for natural circulation systems
Pallippattu Krishnan Vijayan, ... Naveen Kumar, in Single-Phase, Two-Phase and Supercritical Natural Circulation Systems, 2019
3.4.2.1 Single-phase systems
The loss coefficients of commonly encountered flow obstructions such as orifices, sudden contraction and sudden expansion, elbows, U-bends, etc., can be found in Idelchik (1986). However, the loss coefficient data for many special components which exist in rod bundles of nuclear power plants need to be generated experimentally. For many nonstandard pipe components also, the loss coefficient data may be required to be generated experimentally. In such cases, the loss coefficient data are given as a function of the Reynolds number (see Fig. 3.22). For fully developed turbulent flow, the loss coefficient becomes a constant beyond a certain Reynolds number, as shown in Fig. 3.22, and often only this constant value is reported in literature. Hence, frequently it becomes necessary to generate local loss coefficient data, as shown in Fig. 3.22, for the natural circulation loop under study.
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