The majority of the case drying model used in thin layer drying. Are there any drying models available for multi-layer drying or are there similar thin layer models used in multi-layer drying?
Also check https://www.researchgate.net/publication/265275026_Moisture_Ratio_Prediction_in_Drying_Process_of_Agricultural_Products_A_New_Correlation_Model
Also check https://www.researchgate.net/publication/315891089_Modeling_Moisture_Ratio_of_High_Moisture_Potato_Slices_in_Forced_Convection_Multi_Tray_Solar_Dryer
What model do you mean? Do you mean the physical model of the process or you mean the mathematical description of the process in terms of equations/functions.
Mirosław Grzesik Sir, it related to a mathematical model or equation which is used to predict the Moisture ratio like page model, two-term model, Newton, modified page, Henderson and Pabis model, etc.?
also, point out the physical model of the process of the same things.
Then the next question is, do you have kinetic data you want to describe or are your considerations only theoretical. If you have data, I see no obstacles in trying to describe them using the functions mentioned above, treating them as empirical functions. The "models" you mentioned are actually various modifications of the exponential function.
Mirosław Grzesik Yes, Sir, I have experimental data (MR). then your mean that we can use the above model in both of the cases like thin layer and multi-layer drying, only constant will be varying according to the empirical model when fitted to the curve.
Chhotelal Prajapati I think it means non-linear regression of the kinetic data to fit the empirical functions (inverse problem). The empirical model with the lower Root Mean Square-RMS value (0.2 -0.5) most accurately describes the kinetic data and will most likely predict the correct Moisture ratio (MR)
I am not able to answer clearly without first reading the data. If the graphic image of kinetic data is decreasing curves without inflection points, then the exponential function MR=exp(-kt) or the hyperbolic MR=k/(1+kt) or the sum of these functions can be used. However, this will be an empirical description, and the calculated function parameters can only be treated as lumped parameters. However, in the case of several layers, several inflection points (different drying rates) should be expected. Then, perhaps the process needs to be divided into steps of varying drying rate. You can also try to use the sum of functions having an inflection point, for example aiexp(-ktni), i = 1, 2, ... (composition of exponential and power functions).
It is also possible to derive an overall mass balance over the drying particle (s) in form of convection-diffusion-reaction equation. Considering the transport of H20 from the particle core (drying kinetics), diffusion through the pores, successive liquid films (multiple layer) diffusion and advection to the surrounding (external) fluid. The driving force will be the concentration difference between the pore concentration and the bulk (external) fluid-hot air in this case and the multiple liquid films will offer individual mass transfer resistances that should be accounted for in the spatial concentration differential model equation assuming steady state
There is no such technique for ascertaining the exact position (moisture condition) of how much weight loss and diffusion processes occur between layers. If we assume that all layers have the same rate of drying rate or diffusion process then we can apply that model to the prediction of MR.
Do you have any support document or article where is given in detail? please provide me.
Chhotelal Prajapati I agree with you, I was attempting to derive a model of the particle drying process from first principles. Just being creative
But for reference purpose, you can find details in Transport processes and Unit operations-Chapter 9 (3rd edition) by Christie Geankoplis
One can always try to derive an equation based on the mass balance of the individual layers. In the end, however, it has to be verified. The alternative is empirical functions sufficient for design purposes.
- Badges
- Science topic
- Similar topics
- Geoscience
- Asia
- India