Radiative Heat Transfer Analysis in a Marine Boiler Furnace

The improvement of marine boiler furnace has mainly been done emprically. This is due to the complicated phenomena such as combution, heat transfer and flow in the furnace. Among them, heat transfer by radiation is especially important because heat transfer to the furnace wall is mainly done by radiation. New analytical methods are proposed for the radiative heat transfer analysis to increase the accuracy and to reduce the computation time compared with the conventional Monte Carlo method. They are composed of the radiative heat ray method and READ (Radiative Energy Absorption Rate Distribution) method. The radiative heat ray method can calculate the radiative energy transfer from a small element of gas or wall in the furnace to other elements by using nonstochastic method. The result is used repeatedly in the iterational calculation of temperature distribution in the furnace. This method is called the READ method and eliminates the repeated calculation of radiative heat flux during the iteration which is necessary in the conventional Monte Carlo method. Temperature and wall heat flux distribution are calculated by using these methods and experimentally obtained velocity profile and flame shape. The results are compared with the experimental results and show good agreements. The radiative heat transfer diagnosis in the furnace is also carried out. This diagnosis is useful to consider the method to flatten the wall heat flux distribution.