scholarly journals Numerical Simulation of Air Flow and Temperature Distribution in Yarn Drying Room

2012 ◽  
Vol 11 (2) ◽  
pp. 8 ◽  
Author(s):  
Jindarat Pimsamarn ◽  
Panit Kitsubun ◽  
Rabin Tongruk
Keyword(s):  
Standard Deviation ◽  
Moisture Content ◽  
Air Temperature ◽  
Air Flow ◽  
Hydraulic Calculation ◽  
High Accumulation ◽  
Drying Time ◽  
Electricity Cost ◽  
Hot Air ◽  
Drying Efficiency

This research studied the recovery of wasted heat from exhaust air releasing from the compressor to increase the drying efficiency. The yarn drying room model was developed using Computational Fluid Dynamics (CFD) so as to study the distribution of air flow and temperature numerically. The most suitable design of the drying room considering the decrease of drying time such as the locations of hot air inlet and outlet were investigated. At the exhaust air outlet position, the average exhaust air temperature is 56°C, while the average flow rate and relative humidity are 1.75 m/s and 16.2 percent, respectively. The hydraulic calculation revealed that the appropriate duct size was 0.412 x 0.412 m2 width and height. The hot air temperature after transferring through air duct was decreased from 56°C to 52°C. The simulation results showed that the appropriate inlet position is at the ceiling and split into 4 inlet positions which had 0.152 x 0.152 m2 width and height. The most appropriate outlet position was 3 m above the ground in order to achieve the highest distribution of moisture content with standard deviation of 1.9 x 10-4. The locations which had the high accumulation of moisture were at the center and both sides of the drying room due to the low air turbulence. From this configuration, the drying time was decreased from 2 days to 89 minutes. Furthermore, after the 2 air circulators were installed in the drying room, the distribution of moisture content, represented in term of standard deviation, was about 1.5 x 10-4. As a consequence, the drying time could be reduced to 78 minutes, but the monthly electricity cost of air circulators was around 590 baht.

Test Research and Parameter Analysis of Grain Drying Model

2011 ◽  
Vol 66-68 ◽  
pp. 573-576
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Yao ◽  
Ya Qin Li ◽  
Chuang Liu
Keyword(s):  
Moisture Content ◽  
Air Temperature ◽  
Air Flow ◽  
Parameter Analysis ◽  
Mathematics Model ◽  
Drying Process ◽  
Drying Time ◽  
Hot Air ◽  
Grain Moisture ◽  
Grain Drying

The purpose of this study is to explore the effecting principle in the drying process. The factors such as hot air temperature, hot air flow, drying time on the grain moisture content have been all investigated. Using UD to establish the optimization mathematics model which making the grain dryer moisture content as the goal of the design, making the factors of hot air flow, drying time, air temperature as parameters, with the help of UD to analysis the effecting principle of the drying process parameters on the grain moisture content, some references have been provided to the tower dryer.

Characteristics and Process Optimization of Hot-Air Drying Pepper

2012 ◽  
Vol 490-495 ◽  
pp. 3074-3078
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Song ◽  
Ya Qiu Zhang ◽  
Jun Xing Li ◽  
...  
Keyword(s):  
Wind Speed ◽  
Moisture Content ◽  
Air Temperature ◽  
Drying Process ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Primary Parameter ◽  
Hot Air ◽  
Pre Treatment

In order to solve the drying problems in the deep-processing of pepper, peppers were dried through blanching pre-treatment and hot-air drying process. Orthogonal test designs were carried out to investigate factors influencing the quality and moisture content of pepper. The results showed that the whole drying process was a reduction speed drying, hot-air temperature and wind speed have significantly affected on the drying rate of pepper, but the impact of hot-air temperature was more prominent than wind speed; hot-air temperature was found to be the primary parameter to affect the quality of the pepper, wind speed was the secondary one and followed by packing thickness; drying time was found to be the primary parameter to affect the moisture content of the pepper in the drying process, the best drying conditions were as follows: wind temperature was 80°C, wind speed was 10 m/s, packing thickness was 80 cm, drying time was 12 h after 100°C steam blanching pre-treatment

Temperature Distribution of Hot Air Flow in Heating Zone for Drying Application

2014 ◽  
Vol 627 ◽  
pp. 153-157
Author(s):  
Nawadee Srisiriwat ◽  
Chananchai Wutthithanyawat
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Power Supply ◽  
Air Flow ◽  
Heating Zone ◽  
Velocity Control ◽  
Rectangular Duct ◽  
Air Velocity ◽  
Hot Air ◽  
Set Up

The temperature distribution of hot air flow in heating zone of a rectangular duct has been investigated for drying application. The experimental set-up consists of a heater and a fan to generate the hot air flow in the range of temperature from 40 to 100°C and the range of air velocity between 1.20 and 1.57 m/s. An increase of the heater power supply increases the hot air temperature in the heating zone while an increase of air velocity forced by fan decreases the initial temperature at the same power supply provided to generate the hot air flow. The temperature distribution shows that the hot air temperature after transferring through air duct decreases with an increase of the length of the rectangular duct. These results are very important for the air flow temperature and velocity control strategy to apply for heating zone design in the drying process.

scholarly journals Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.)

2012 ◽  
Vol 1 (2) ◽  
Author(s):  
Nihar Ranjan Sahoo ◽  
Uma Sankar Pal ◽  
Sanjaya Kumar Dash ◽  
M.D. K. Khan
Keyword(s):  
Heat Pump ◽  
Air Temperature ◽  
Colour Change ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Hot Air ◽  
Thin Layer Drying ◽  
Quality Aspects ◽  
Heat Pump Drying ◽  
Air Dryer

A prototype heat pump dryer has been developed for drying of fruits and vegetables at low temperature and relative humidity to maintain the quality of dried product. Onions, of Nasik red variety were peeled, trimmed and sliced to 2 mm thickness. The onion slices were dried in the heat pump dryer at 35ºC (32 % R.H.), 40ºC (26 % R.H.), 45ºC (19 % R.H.) and 50ºC (15 % R.H.). Samples were also dried in a hot air dryer at 50ºC (52 % R.H.) for comparison. The drying rate increased with increase in drying air temperature, associated with reduced R.H., in the heat pump dryer. Drying took place mainly under the falling rate period. The Page equation, resulting in a higher coefficient of determination and lower root mean square error, better described the thin-layer drying of onion slices than the Henderson and Pabis equation. Heat pump drying took less drying time of 360 min and yielded better quality dried product, with higher retention of ascorbic acid and pyruvic acid and lower colour change, as compared to a hot air dryer at the same drying air temperature of 50ºC.

Optimization of Drying Kinetics and Quality Parameters of Broccoli Florets

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Andrea V Mahn ◽  
Paola Antoine ◽  
Alejandro Reyes
Keyword(s):  
Antioxidant Activity ◽  
Air Temperature ◽  
Flow Rate ◽  
Air Flow ◽  
Radical Scavenging ◽  
Particle Diameter ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Air Flow Rate ◽  
Drying Time

Drying kinetics of broccoli florets in a tunnel dryer was studied. Effective moisture diffusivity (Deff) and activation energy for moisture diffusion (E0) were estimated. The effect of air temperature, air flow rate and particle size on antioxidant capacity, greenness and texture were calculated through a 23 factorial design. Air flow rate and temperature significantly affected drying time. Deff fluctuated between 2.82 x 10-10 and 2.00 x 10-9 (m2/s), and E0 was around 42 KJ/mol, agreeing with values reported in literature. The maximum antioxidant activity was obtained at 60°C, air flow rate of 4 m/s and 1.5 cm particle diameter, resulting in a 70 percent reduction in free radical scavenging ability and a 29 percent increase in total reductive capability. Air temperature had significant effect on greenness, and air flow rate significantly affected texture. The optimization of convective drying of broccoli allows maximizing antioxidant activity and minimizing cost by saving energy and time.

Experiments on Hot-Air and Infrared Drying Characteristics of LiCoO2 Cathode Coating for Lithium-Ion Battery

2020 ◽  
Vol 1003 ◽  
pp. 260-267
Author(s):  
Xian Feng Wu ◽  
Xu Jia Li ◽  
Xin Zhi Bei
Keyword(s):  
Lithium Ion Battery ◽  
Radiation Power ◽  
Influencing Factor ◽  
Lithium Ion ◽  
Drying Time ◽  
Infrared Drying ◽  
Hot Air ◽  
Constant Rate ◽  
Drying Conditions ◽  
Drying Efficiency

Based on the drying technology principle of lithium-ion battery cathode coating, the variation law of dry base moisture content and drying rate in the process of hot-air drying and infrared drying was studied. The experimental results show that the cathode coating of lithium-ion battery dried under hot-air and infrared conditions can be divided into three stages: increasing-rate, constant-rate, and falling-rate. The constant-rate stage is the main drying stage, accounting for more than 50% of the weight loss, the falling-rate stage is the main energy consumption stage, accounting for more than 50% of the time. Under the condition of hot-air, the change level of airspeed is the main influencing factor of the drying process, and the drying time can be reduced by about 35% for each 0.7 m/s increase in airspeed. Under infrared conditions, the change level of radiation power is the main influencing factor of the drying process, and the drying time can be reduced by about 34.1% for every 100W of power increase. The optimal drying conditions under hot-air conditions are: air temperature 90 °C, airspeed 2.3 m/s; the optimal drying conditions under infrared conditions are: radiation distance 13 cm, radiation power 200 W. By comparing the best conditions of hot-air and infrared, it can be known that the drying efficiency is higher in the infrared condition and the drying duration is 160 s, but the energy utilization rate in the falling-rate stage in the infrared condition is lower than that in the hot-air condition. Therefore, when infrared drying enters the falling-rate stage, it can be supplemented by hot-air drying to further improve the drying efficiency.

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.

scholarly journals Quality of Milled Rice from Large-Scale Dried Paddy Rice by Hot Air Combined with Radio Frequency Heating

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2277
Author(s):  
Karn Chitsuthipakorn ◽  
Sa-nguansak Thanapornpoonpong
Keyword(s):  
Moisture Content ◽  
Radio Frequency ◽  
Block Design ◽  
Specific Energy Consumption ◽  
Brown Rice ◽  
Convective Drying ◽  
Control Treatment ◽  
Rf Heating ◽  
Drying Time ◽  
Hot Air

A scaled-up process for paddy drying was developed using hot air (HA) combined with radio frequency (RF) heating. The study was conducted using hot air (control treatment) arranged in descending order in four temperature levels, namely 80 °C at moisture content of 25–26%, 70 °C at moisture content of 20–25%, 60 °C at moisture content of 17–20%, and 50 °C at moisture content of 13–17%, as well as with hot air combined with radio frequency (HA/RF) at different paddy temperatures (45–60 °C) by adjusting the appropriate RF energy when passing through RF heating chamber, namely HA/RF45, HA/RF50, HA/RF55, and HA/RF60. Each treatment was performed in three replicates and data were statistically analyzed in a randomized complete block design. The quality attributes of paddies affected by the drying process were assessed: fissure percentage, color, milling quality, and sensory evaluation. The drying efficiency showed that the drying time and the specific energy consumption could be decreased by up to 54.44% and 23.17% at HA/RF60 and HA/RF45, respectively. As the RF heating temperature increased, the fissure percentage of brown rice kernels at HA/RF45 and HA was not significantly impacted. Regarding color evaluation, combining RF heating and convective drying at all given conditions could be statistically applied in terms of the b*, WI, and ΔE* value. Considering the milling yield of HA as the baseline, head rice yield was maximized at HA/RF45, while bran yield reached the maximum at HA/RF60. The liking score of cooked rice after it was dried using the HA method was the highest. This study concludes that the HA/RF45 was the most appropriate drying condition, and this may provide preliminary exposure to the industrial drying of paddies.

scholarly journals Energy efficiency and physical integrity of maize grains subjected to continuous and intermittent drying

2021 ◽  
Vol 25 (10) ◽  
pp. 710-716
Author(s):  
Geraldo A. Mabasso ◽  
Valdiney C. Siqueira ◽  
Wellytton D. Quequeto ◽  
Rodrigo A. Jordan ◽  
Elton A. S. Martins ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Moisture Content ◽  
Energy Demand ◽  
Air Flow ◽  
Specific Energy Consumption ◽  
Fixed Bed ◽  
Membrane Integrity ◽  
Drying Time ◽  
Cell Membrane Integrity ◽  
Tempering Time

ABSTRACT Grain drying is a common process, due to its need for the maintenance of quality, but it is the activity with the highest energy demand among the postharvest stages. Thus, this study aimed to evaluate the effect of different tempering times on the energy efficiency of drying process and maintenance of cell membrane integrity of maize grains harvested with moisture content at 0.34 ± 0.01 d.b. The grains were dried in an experimental fixed-bed dryer with control of temperature and air flow conditions. The experiment was conducted in a completely randomized design with five tempering times (0, 4, 8, 12 and 16 hours) and four repetitions, where zero corresponds to continuous drying, while the remaining times correspond to the intermittent dryings. The grains were dried at the temperature of 100 ºC and air flow of 15.4 m3 min-1 t-1 until reaching moisture content of 0.16 ± 0.03 d.b. For intermittent drying, the process was interrupted with 0.22 ± 0.02 d.b. and restarted after the tempering time. The increase of tempering time led to reductions in effective drying time, specific energy consumption, electrical conductivity and damage and increase in the drying rate and overall energy efficiency. Intermittent drying reduced the drying time, being 30.25% more efficient than continuous drying.

Thin-Layer Mathematical Modeling of Turmeric in Indirect Natural Conventional Solar Dryer

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Masnaji R. Nukulwar ◽  
Vinod B. Tungikar
Keyword(s):  
Mathematical Modeling ◽  
Moisture Content ◽  
Thin Layer ◽  
Air Velocity ◽  
Drying Time ◽  
Sun Drying ◽  
Solar Dryer ◽  
Air Temperatures ◽  
Drying Efficiency ◽  
Kinetics Of

Abstract The objective of this study is to find an optimized thin-layer mathematical model suitable for drying kinetics of turmeric. Turmeric has a high moisture content which necessitates effective drying. A 10 kg, sample batch, of turmeric was dried in a solar dryer. Drying air temperatures and air velocity were observed in the range of 55 °C–68 °C and 0.7 m/s–1.4 m/s, respectively, in the drying experiments. It is seen that the moisture content of the turmeric is reduced from 77% to 11.93% in 22 h when compared with open sun drying, which required 60 h for the same reduction in the moisture content. Scheffler dish was used to generate steam for the dryer. Seven thin-layer mathematical models, cited in the literature, had been used for the study. These models were applied for different trays placed in the dryer. The result of the research and experimentation showed that the Page model fits best for drying in the steam-based dryer and open sun drying. Experimental results showed 63.33% saving in drying time, and the drying efficiency was found as 29.85%. Uncertainty in the drying efficiency was observed as 0.67%. Experimental investigation and the findings from the mathematical modeling are presented in this paper.

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