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ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

DETERMINATION OF THE STEADY STATE TEMPERATURE FIELD IN NATURALLY OIL-COOLED DISC-TYPE TRANSFORMERS

Get access (open in a dialog) DOI: 10.1615/IHTC6.2120
pages 123-128

Аннотация

In naturally cooled transformers the mass flow of the cooling oil is maintained by the thermosyphon effect. The difference of pressure produced by the thermosyphon can be determined from the temperature field in the coil and in the heat exchanger.
Under otherwise identical conditions, the mass flow rate of the oil is influenced by the flow resistance of the flow-pipe system which is highly temperature dependent. At the same time the mass flow rate of the oil has an effect upon the temperature field.
For the solution of the coupled problem a simultaneous and hierarchic model, is discussed which is based on the heat and mass flow network method. Steps of the computer-aided method are as follows: The mass flow network model of the transformer is prepared and the equation system for non-isothermic flow conditions is written. The heat flow network model of the coil is prepared in which the flow of heat capacitance of the cooling media corresponds to the branch fluxes in the mass flow network, and the equation system of the network is written. By solving the linearized equation system, the nodal temperatures and the nodal pressures are determined and the values of the oil flow rate made more accurate by multiple iteration.