Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Agricultural and Biosystems Engineering


A vortex type biomass furnace was tested for converting corn cobs into thermal energy. The performance of the furnace was determined by a series of 13 tests. Two independent variables were studied: corn cob feeding rate, and air damper opening. Response surface method of analysis was used to statistically analyze the results of the tests;The results showed that three dependent variables were affected by corn cob feeding rate and air damper opening; there were: stack temperature, furnace efficiency, and percent of excess combustion air. Interpretations from the response surfaces of these parameters can be safely made. Contour plots for all dependent variables, and an example of the furnace performance prediction, were given. The furnace efficiency was calculated by using the ratio of actual ethalpy to maximum enthalpy, and this method was found to be suitable for this type of furnace. Particulate matter emissions were determined. The quantity of particulate matter emissions was not significant within the range of the experiment;A corrosion test was conducted to determine the corrosion rate for four metals: mild steel, aluminum, galvanized sheet metal, and brass. The corrosion rate of brass and mild steel was high. The corrosive agents were probably SO(,2), HCl, and Cl(,2) gases which were found in the combustion products;A dimensional analysis study was conducted to determine the effect of furnace and fuel parameters on the heat released from the furnace. Six (pi) terms were developed, and three of them held constant. It was found that the air to fuel ratio was the major factor for wood chips, corn stalks, and corn cobs, while the absolute temperature was the main parameter for soybean straw. The dryer blower created a negative pressure inside the furnace which affected the results of 1981 data for burning corn cobs.



Digital Repository @ Iowa State University,

Copyright Owner

Mohamed Fouad Ismail Wahby



Proquest ID


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File Size

167 pages