Design and Simulation of Radial Flow Turbine Impeller and Investigation Thermodynamic Properties of Flow in LE and TE

Centrifugal (radial flow) turbines are widely used in various industries, including power generation industries, so the study on them is of particular importance. The aim of this study was to investigate the thermodynamic properties of fluid flow in Trailing Edge (TE) and (LE) Leading Edge. For this purpose, first, the rotor (impeller) of the radial flow turbine was designed based on some design data such as flow rate, number of blades, rotational speed, diameter and length of the impeller, and then the designed rotor was simulated in 3D. The simulation done in the pressure based method and the turbulence model is SST and the rotational speed was 140,000(RPM). The results showed that the pressure, temperature and enthalpy in TE are less than LE and the areas close to the hub have the highest pressure. Another phenomenon observed is that in the section LE we see the separation of the flow from the blade surface, which then approaches the blade surface again and follows a relatively regular path,so the entropy in TE is greater than LE. At the end, the results of numerical solution were compared with valid data and the error rate and its reasons were discussed.

The effect of laser on the efficiency of membrane clarification of pomegranate juice

In this study, a laser node with power 1 W and wavelength 532 nm was used to reduce the membrane fouling and evaluate its effect on the efficiency of membrane clarification of pomegranate juice. The results showed that the permeate flux increased in the presence of the laser due to the decrease in total resistance. Also, application of the laser in the pressurized process of 0.5 bar and the flow rate of 10 mL s^-1 had the best performance on the permeate flux. In addition, the laser alignment is an important parameter that gives the most efficiency in case of the vertical angle and the large surface exposure. This was confirmed by images obtained by scanning electron microscope. Evaluation of physicochemical properties of the pomegranate juice showed that they changed after membrane clarification; however, the rate of changes in the most parameters (except pH, total soluble solids content and color parameters) in two processes with and without the laser was same.

CFD simulation and experimental validation of in-container thermal processing in Fesenjan stew

The purpose of the study was to develop and validate the CFD model for predicting temperature profile and determine the slowest heating zone (SHZ) during the thermal processing of Fesenjan stew. The temperature profile was recorded experimentally at a point where it was predicted to be the SHZ. The results showed that the SHZ was located at the geometric center of the containers, and the temperature reached 120.3 °C. The average temperatures of experiment versus predicted temperatures at the same positions, no significant difference were observed (p < .01). The RMSE calculation showed good agreement between simulation and experimental data (RMSE = 1.36). The container geometrical center F0 was measured 17.68 min and indicated that an additional process was applied. An 11.5 min reduction in holding time was estimated to optimize the process since the F0 of some meat and sauce-based food is about 6-7.65 min.

Numerical simulation of conductive heat transfer in canned celery stew and retort program adjustment by computational fluid dynamics (CFD)

In this study, conductive heat transfer was investigated during sterilization in the canned celery stew. A computational fluid dynamics CFD model was developed and validated to predict the temperature profiles and determine the slowest heating zone (SHZ) during the thermal processing. The temperature profile was obtained and recorded experimentally at a point where the coldest thermal point was expected. CFD models were validated against experimental data. The results of the study showed that the SHZ was located at the geometric center of the containers (x = 5.00, y = 1.42, z = 6.75 cm), and the temperature reached 119.5 °C. Root mean square error (RMSE) was calculated and showed a good fit between both methods (RMSE = 1.03). The container geometrical center F0was estimated to be 13.19 min. For optimization of the process, according to the stew ingredients, especially meat, F0was about 8 min. Thus, the required holding time was decreased by 5.19 min, and the retort setting was readjusted.