STUDIES RELATED TO AIR FLOW RESISTANCE AND PRESSURE DROP AND DRYING A COMPARATIVE STUDY ON USING HEATED FORCED AIR AND SOLAR ENERGY FOR DRYING ONIONS

Abstract

The economical drying operation has bee the subject of investigation for several years. The main purpose of this study was to provide a useful information on predicting the drying methods of agricultural materials in order to design, improve and calculating the economical operating conditions of drying systems. In addition, the power requirement of the systems to be calculated for any proposed operating conditions.

So, experiments have been carried out to measure the moisture content of drying time, the rate of drying and characteristic curves of onion variety El-Behery. To carry out the work, two drying methodsincluding solar energy and forced heated air were used.

The objectives of this work were:

1- To study the effect of two different drying methods including heated forced air and solar energy on onion drying curves and drying rates. 2- To indicate the effect of three different air flow rates and two different levels of temperatures on characteristic curves of drying onion. 3- To develop new formulas for drying onion.

4- To compare between the cost of the two different drying methods.

The first experiment of Using forced heated air on drying onion were carried out in the research laboratory of agricultural Mechanization Department, Faculty of Agriculture, Kafr El-Sheikh, Tanta University.

The second experiment of using green house on drying onion were carried out in Rice Mechanization Center at Meet El-Deeba, Kafr El­ Sheikh Governorate, Egypt.