A MATHEMATICAL MODEL FOR DYNAMIC ANALYSIS OF A BOILER

The paper outlines a mathematical model of an oil fired boiler for a steam production of about 95 t/h which comprehends the whole boiler system from the inlet of fuel oil, air and water to the outlet of superheated steam. Special attention is paid to the calculation of water circulation and two-phase flow of water and steam in the risers. This makes it possible to calculate variations of the drum water level due to swell and shrink. The differential equation system, which is of the 12th order, is solved by a digital computer, Univac 1108, the computation time being about 1/10th of the real time for the process. The model is primarily adjusted to a Foster Wheeler boiler type ESD 11. To verify the results obtained from the calculation comprehensive tests have been carried out by Det Norske Veritas on the same type of boiler on board a ship, the T/T OCTAVIAN, Hilmar Reksten Shipping Co. The results obtained from the calculation and from the tests are given in the paper.