Optimum heating of cylindrical pressure components weakened by holes

• Autorzy: Dzierwa P. , Taler J.
• Języki publikacji: EN

Abstrakty

EN

A method for determining time-optimum medium temperature changes is presented. The heating of the pressure elements will be conducted so that the circumferential stress caused by pressure and fluid temperature variations at the edge of the opening at the point of stress concentration, do not exceed the allowable value. In contrast to present standards, two points at the edge of the opening are taken into consideration. The first point, P[1], is located at the cross section and the second, P[2], at the longitudinal section of the vessel. It will be shown that the optimum temperature courses should be determined with respect to the total circumferential stress at the point P[2], and not, as in the existing standards due to the stress at the point P[1]. Optimum fluid temperature changes are assumed in the form of simple time functions. For practical reasons the optimum temperature in the ramp form is preferred. It is possible to increase the fluid temperature stepwise at the beginning of the heating process and then increase the fluid temperature with the constant rate. Allowing stepwise fluid temperature increase at the beginning of heating ensures that the heating time of a thick-walled component is shorter than heating time resulting from the calculations according to EN 12952-3 European Standard. @eng

Słowa kluczowe

EN

boiler standards; heating optimization; inverse heat conduction problem; pressure vessels; thermal stress

PL

kotły; naprężenie termiczne; normy; odwrotne zagadnienia przewodzenia ciepła; optymalizacja nagrzewania; zbiorniki ciśnieniowe

• Wydawca: Wydawnictwo Instytutu Maszyn Przepływowych PAN ; Komitet Termodynamiki i Spalania PAN
• Czasopismo: Archives of Thermodynamics
• Rocznik: 2012
• Tom: Vol. 33, no. 3
• Strony: 111--121
• Opis fizyczny: Bibliogr. 5 poz.,Rys., tab.,

Twórcy

autor

Dzierwa P.

autor

Taler J.

• Cracow University of Technology, Department of Thermal Power Engineering, Faculty of Mechanical Engineering, Al. Jana Pawła II 37, 31-864 Cracow, Poland,

Bibliografia

• [1] TALER J., DZIERWA P.: Proposition of new rules for determining allowable medium temperature rates during heating and cooling of thick-walled steam boiler components. Arch. Thermodyn 37(2007), 1-2, 91-108.
• [2] TALER J., DZIERWA P., TALER D.: Optimum heating of pressure components of large steam boilers. Forschung im Ingenieurwesen 73(2009), 3, 183-192.
• [3] TALER J., DZIERWA P.: A new method for optimum heating of steam boiler pressure components. Int. J. of Energy Res 35(2011), 897-908.
• [4] DZIERWA P.: Determining of allowable heating and cooling rates of boiler pressure components using the quasi steady-state theory. Energetyka 65(2012), 1, 601-606 (in Polish).
• [5] NODA N., HETNARSKI R. B., TANIGAWA Y.: Thermal Stresses. Taylor & Francis, New York 2003.