The effect of drying parameters on the drying-rate constant, the diffusion coefficient, and the dynamic equilibrium moisture content was investigated using the Park variety of wheat. The initial moisture content of all the grain used in the drying tests was approximately 29 percent, dry basis. Air temperatures of 120, 100, 80 and 60 degrees Farenheit; air flow rates of 120, 80, 20 and 5 feet per minute and several relative humidities were employed as the drying conditions during the tests. A closed cycle, heated air dryer in which the air temperature and the relative humidity could be controlled to ± 2 degrees Farenheit and ± 5 percent respectively, was constructed for the investigation. It was assumed that the mechanism of internal flow of moisture within a kernel is that of diffusion. When the initial transition drying period was neglected, the drying-rate constant and the diffusion coefficient were found to be constant and the plot of log moisture ratio against time gave an excellent fit for each drying test. It was concluded that the falling-rate period in thin layer drying could be represented by a constant drying-rate constant and diffusion coefficient. The effect of air temperature on the drying-rate constant and diffusion coefficient was found to be inconsistent with an Arrhenius type equation. There was no observable effect due .to air flow rate and relative humidity of the drying air. The dynamic equilibrium moisture content increased with increased relative humidity of the air. A plot of log dynamic equilibrium moisture content versus log-log relative humidity gave a straight line relationship and satisfied Henderson's equation. The equilibrium constants were found to vary with the air temperature. The dynamic equilibrium moisture content was found to decrease with both the air temperature and air flow rate. The effect of air flow rate was quite small except at low' temperatures. When log air temperature was plotted against dynamic equilibrium moisture content, it followed a straight line, indicating that an exponential relationship between the two might exist. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

LD2668 .T4 1954 D7 / Master of Science

Call number: LD2668 .T4 1956 H37 / Master of Science

In the agricultural industries drying plays a major role as its very important for grain storage. The selection of the dryer and the method used for drying should be chosen wisely considering the product to be dried with its other factors. Generally, a dryer and its method are taken into account based on the output product quality and considerable energy consumption given during drying. This thesis is based on finding out the optimal energy consumption obtained while drying the wheat grain using the integrated infrasound technology through conducting experiments and analyzing the process of drying with the CFD model. The thesis work covers physical experiments, determination of the relation between infrasound parameters, and evaluation of the drying in CFD simulation, to analyze the drying process. The experiments are done to predict the relation between the drying and the other main parameters like sound frequency, sound pressure, piston displacement, cycle time, and the airflow rate. The experiment procedure and requirements are clearly formulated accordingly. The experimental results are later compared with the theoretical data to check the expected output. The dryer capacity varies with the cycle time, temperature, and sound wave. The CFD simulation is executed to study the air flow velocity, temperature and the fluidization condition of the particle. To compare the energy consumption of the drying system a conventional air dryer is selected here. The results of this study show that infrasound-integrated technology has a relatively low energy consumption, but will have a high cost for installation and maintenance. / Inom jordbruksindustrin spelar torkning en viktig roll eftersom den är mycket viktig för lagring av spannmål. Valet av torktumlare och den metod som används för torkning bör väljas klokt med hänsyn till följande den produkt som ska torkas och andra faktorer. I allmänhet väljs en torktumlare och dess metod för att och metod utifrån produktens kvalitet och den betydande energiförbrukningen. under torkningen. Denna avhandling är baserad på att ta reda på den optimala energiförbrukning som erhålls genom atttorkning av vetekorn med hjälp av den integrerade infrasound-tekniken genom att genomföra en experiment och analysera torkningsprocessen med CFD-modellen. Avhandlingen omfattar fysikaliska experiment, fastställande av förhållandet mellan infraljud och parametrar och utvärdering av torkningen i CFD-simulering för att analysera torkningsprocessen. Experimenten görs för att förutsäga förhållandet mellan torkningen och de andra huvudparametrarna såsom ljudfrekvens, ljudtryck, kolvförskjutning, cykeltid och luftflödeshastighet. Det experimentella förfarandet och kraven är tydligt formulerade i enlighet med detta. Försöket resultaten jämförs senare med de teoretiska uppgifterna för att verifiera det förväntade resultatet. Torktumlaren kapaciteten varierar med cykeltid, temperatur och ljudvåg. CFD-simuleringen är utförs för att studera luftflödeshastighet, temperatur och fluidiseringstillstånd för partikeln. För att jämföra torkningssystemets energiförbrukning väljs en konventionell lufttork här. Resultaten av den här studien visar att infrasound-integrerad teknik har en relativt låg energiförbrukning, men kommer att ha en hög kostnad för installation och underhåll.