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# Berková E. - Algorithm of unsteady 1d calculation for feed water temperature analysis in insulated feed water piping during start up and shut down procedure of hp regenerative heaters

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Презентація учасника VIII Міжнародної літньої ядерної школи, яка пройшла на Рівненській АЕС у липні 2019 року

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### Berková E. - Algorithm of unsteady 1d calculation for feed water temperature analysis in insulated feed water piping during start up and shut down procedure of hp regenerative heaters

1. 1. ALGORITHM OF UNSTEADY 1D CALCULATION FOR FEED WATER TEMPERATURE ANALYSIS IN INSULATED FEED WATER PIPING DURING START UP AND SHUT DOWN PROCEDURE OF HP REGENERATIVE HEATERS Bc. Eva BERKOVÁ LSJI UA 2019
2. 2. • Introducing the topic • Start up procedure of HP regenerative heaters • Shut down procedure of HP regenerative heaters • Describing of creation of analytic calculation • Comparing of results of analytic calculation with results of numeric calculation • Summary CONTENT
3. 3. INTRODUCING THE TOPIC MOTIVATION low cycle fatigue of HP regenerative heaters TARGET solve unsteady process of feed water temperature in piping → create unsteady 1D analytic calculation in program MS Excel and compare results with results of numeric calculation
4. 4. START UP PROCEDURE OF HP REGENERATIVE HEATERS Name Mark Value Unit Piping outside diameter do 168,3 mm thickness s 17,5 mm length L 10 m material − 16Mo3 − density ρ 7850 kg m3 thermal conductivity λW 42,5 W m ∙ K specific thermal capacity cp 482 J kg ∙ K default temperature TW 20 ℃ Feed water pressure p 135 bar inlet temperature TF,in 100 120 157 ℃ mass flow rate m 1 5 20 kg s default temperature TF 20 ℃ Table 1: Task for start up procedure of HP regenerative heaters
5. 5. SHUT DOWN PROCEDURE OF HP REGENERATIVE HEATERS Name Mark Value Unit Piping outside diameter do 168,3 mm thickness s 17,5 mm length L 1 m material − 16Mo3 − density ρ 7850 kg m3 thermal conductivity λW 42,5 W m ∙ K specific thermal capacity cp 482 J kg ∙ K default temperature TW 100 120 157 ℃ Insulation thickness s 80 mm material − Isover ML-3 − density ρ 25 kg m3 thermal conductivity λizol 0,043 W m ∙ K specific thermal capacity cp 840 J kg ∙ K protective sheet metal relatively radiation ε 0,5 − Feed water pressure p 135 bar mass flow rate m 0 kg s default temperature TF 100 120 157 ℃ Air temperature T∞ 20 ℃ pressure p∞ 1 bar Table 2: Task for shut down procedure of HP regenerative heaters
6. 6. DESCRIBING OF CREATION OF ANALYTIC CALCULATION Start up procedure of HP regenerative heaters Shut down procedure of HP regenerative heaters heat conduction in longitudinal direction is neglected air is dry heat conduction of insulation, heat conduction of protective sheet metal and radiation is neglected influence of front of piping is neglected all radiant heat is absorbed of air heat conduction of protective sheet metal is neglected Material properties of piping and insulation are unchangeable with temperature Pressure drop is neglected Table 3: Assumptions for simplification of analytic calculation Macro in MS Excel
7. 7. DESCRIBING OF CREATION OF ANALYTIC CALCULATION
8. 8. COMPARING OF RESULTS OF ANALYTIC CALCULATION WITH RESULTS OF NUMERIC CALCULATION 0 20 40 60 80 100 120 140 0.0 1.0 2.0 3.0 4.0 5.0 TF [°C] t [min] Trend of feed water temperature in time - Variant 120 °C, 5 kg/s analytic calculation numeric calculation
9. 9. Numeric simulation for start up procedure of HP regenerative heaters in time 26 sec – Variant 120 °C, 5 kg/s COMPARING OF RESULTS OF ANALYTIC CALCULATION WITH RESULTS OF NUMERIC CALCULATION
10. 10. COMPARING OF RESULTS OF ANALYTIC CALCULATION WITH RESULTS OF NUMERIC CALCULATION 12.76 3.77 1.56 12.51 13.02 14.83 3.97 1.31 14.23 15.63 120°C, 1 kg/s 120°C, 5 kg/s 120°C, 20 kg/s 100°C, 1 kg/s 157°C, 1 kg/s t [min] Variant Time for reheating of piping analytic calculation numeric calculation
11. 11. SUMMARY Two algorithms for unsteady 1D heat transfer calculation in program MS Excel • enable fast unsteady calculation of feed water temperature in the piping • make for imagination about behavior of feed water temperature during start up and shut down procedure of HP regenerative heaters • can substitute complicated and time consuming numeric simulation
12. 12. SOURCE • BERKOVÁ, E. Příprava algoritmu nestacionárního 1D výpočtu pro vyšetření průběhu teploty izolovaného potrubí plného vody při najíždění a odstavování VT regenerace. Plzeň: Západočeská univerzita v Plzni, Fakulta strojní, 2019.
13. 13. THANK YOU FOR YOUR ATTENTION!