الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
In this research, the thermal properties for the yeast were measured for a temperature range from 3 to 33°C. The measured properties were; the thermal conductivity the thermal diffusivity and the density Over the studied temperature range the temperature has a minor effect on the thermal properties. To preserve the yeast and other food products a mathematical model for the fluid flow heat transfer inside cold stores was predicted. The mathematical model was based on a specified arrangement for the yeast inside the cold stores. The mathematical model showed the main parameters which affect on the temperature-time history and the cooling time. These parameters are; air Reynolds number, yeast dimensions, yeast thermal properties and the distance between yeast blocks. To solve the mathematical model, a general three-dimensional unsteady elliptic computer code was designed. The program is based on the finite volume SIMPLE algorithm. To improve results’ convergence rate eight recent modifications by different investigators were considered through. designing the computer program. In addition, two new recommendations were suggested to improve the convergence rate too via improving the boundary conditions coupling and the outflow condition. The code was found to be very efficient in both computational time and results’ accuracy. The numerical results showed the effect of the studied parameters on the total cooling time, the maximum and bulk temperatures-time history. Finally, ID evaluate the validity of the theoretical results, an experimental work was carried out. The temperature-time history inside yeast block was measured and compared with the the theoretical values. The comparison showed that the theoretical results were in a good agreement with the experimental measurements.