scholarly journals New methodology and instrument for determination of the isothermal drying rate of cotton and polypropylene fabrics at constant air velocity

2019 ◽  
Vol 14 ◽  
pp. 155892501987348
Author(s):  
Tereza Heinisch ◽  
Vladimír Bajzík ◽  
Luboš Hes
Keyword(s):  
Current Method ◽  
Woven Fabrics ◽  
Drying Rate ◽  
Air Velocity ◽  
Reliable Measurement ◽  
Drying Time ◽  
Vapour Permeability ◽  
Related Method ◽  
Isothermal Drying

The most important parameters characterizing thermal comfort of garments are thermal resistance and water vapour permeability. Contrary to common garments, protective and sport garments (dresses) are often used in wet state (due to the absorbed sweat), which affects their comfort properties. That is why testing of both mentioned parameters in recent became important, along with the determination of the drying rate and drying time of sport dresses and underwear. However, current method of the drying rate mostly does not enable reliable measurement of this parameter, mostly due to non-isothermal conditions during the measurement and unknown velocity of the drying rate. In the article, a new method and instrument determination of the isothermal drying rate and drying time of sport dresses and underwear are presented, which is executed under at constant velocity of the parallel air flow. The reliability of the instrument and related method was verified by determination of the drying rate of selected woven fabrics.

Effect of Air Velocity and Temperature on the Drying Kinetics of Drumstick Leaves (Moringa Oleifera)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Monica Premi ◽  
Harish Sharma ◽  
Ashutosh Upadhyay
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Moringa Oleifera ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Kinetics Of

Abstract The present study examines the effect of air velocity on drying kinetics of the drumstick leaves in a forced convective dryer. The drumstick leaves were dried in the temperature range of 50–800 C, at different air velocity (Dv) of 0.5 and 1.3 m/s. The results indicated that drying temperature and air velocity are the factors in controlling the drying rate. Experimental data obtained for the samples for color, drying rate and drying time proved that air velocity of 1.3 m/s yielded the product superior in terms of both quality and energy efficiency as compared to the samples at 0.5 m/s. Activation energy for drumstick leaves dried with air velocity, 0.5 and 1.3 m/s was 12.50 and 32.74 kJ/mol respectively. The activation energy relates similarly with the effective moisture diffusivity which also increased with increase in air velocity and temperature.

scholarly journals DETERMINATION OF DRYING TIME OF THE RAMMED EARTH WALLS

2018 ◽  
Vol 15 ◽  
pp. 81-87
Author(s):  
Tereza Plaček Otcovská ◽  
Barbora Mužíková ◽  
Pavel Padevět
Keyword(s):  
Building Material ◽  
Main Idea ◽  
Rammed Earth ◽  
Drying Rate ◽  
Drying Time ◽  
History Of ◽  
Rate Experiment ◽  
History Of Use ◽  
Earth Walls

The unburned earth is a building material with long history of use. Buildings made of unburned clay are all over the world. But at present, unburned earth is minority building material and its properties are not sufficiently investigated. The rammed earth is one of main kind of unburned earth. This paper is focused on drying rate of the rammed earth of known composition. The significant part of the paper is focused on principle of our own research and the main idea of our research is explained here. The second part of the paper is devoted to drying rate experiment and measured results from this experiment. Determination of drying time of universal rammed earth walls is the main result of the experiment.

Determination of Moisture Diffusivity and Activation Energy in Thin Layer Drying of Olive Pomace

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Smail Meziane ◽  
Naima Mesbahi
Keyword(s):  
Activation Energy ◽  
Thin Layer ◽  
Moisture Diffusivity ◽  
Olive Pomace ◽  
Air Velocity ◽  
Drying Time ◽  
Effective Moisture ◽  
Air Temperatures ◽  
Thin Layer Drying

Abstract The thin layer drying of olive pomace was experimentally studied in a laboratory convective dryer. Drying experiments were performed under five air temperatures of 60, 70, 80 and 90ºC, two air velocities of 1.0 and 1.8 m s-1 and three thickness of thin layer of 6, 9 and 12 mm. The results show that the drying time decreased with increased in drying temperature and air velocity but increased with the decreasing of thin layer thickness of olive pomace. Over the experimental range studied, the values of effective moisture diffusivity and activation energy ranged from 1.25 • 10-9 to 6.30 • 10-9 m2 s-1 and 26.30 to 37.63 kJ mol-1, respectively. The dependence of these parameters on thickness of thin layer, and temperature and velocity of drying air has been investigated.

scholarly journals A study of drying parameters on drying time and colour quality of grated coconut using tumbling mechanism in convective dryer

Food Research ◽  
2020 ◽  
Vol 4 (S6) ◽  
pp. 64-69
Author(s):  
S. Yahya ◽  
A. Mohd Shahrir ◽  
M.A. Amir Syariffudden ◽  
A. Shafie ◽  
J. Mohammad Shukri ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Small Scale ◽  
Drying Rate ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Significant Difference ◽  
Main Factors ◽  
Drying Behaviour

A small scale convective dryer with tumbling mechanism was specially constructed for drying grated coconut. This new drying mechanism was evaluated in term of drying behaviour and colour quality of the final product. Three main factors that involved were hot air temperature, rotational speed (rpm) and air velocity. Every combined parameter of a sample was compared to each other and also with freshly grated coconut. It was found that the combination of 60°C, 6 rpm and 4.31 ms-1 had the shortest drying time as well as the highest drying rate among other combinations. In contrast, combination factors of 50° C, 3 rpm and 2.06 ms-1 had the lowest drying rate. Three main factors; temperature, rotational speed and air velocity were significantly contributed to the response of drying time as (p<0.05). Drying rate also increased with increase in temperature, rotational speed and air velocity. In term of colour analysis (L*, a*, b*), there was a significant difference among dried grated coconut samples. Nevertheless, sample 60˚C, 3 rpm and 4.31 ms-1 and 50˚C, 3 rpm and 4.31 ms-1 showed no significant different (p>0.05) in lightness when compared to freshly grated coconut hence excellent in retaining its original appearance. On top of that, sample (60˚C, 3 rpm and 4.31 ms-1 ) also achieved considerable drying rate with an acceptable drying time of 135 mins.

scholarly journals Drying kinetics of mango fruit using tray and oven dryer

2020 ◽  
Vol 3 (2) ◽  
pp. 51
Author(s):  
Nurhasmanina Norhadi ◽  
Ammar Mohd Akhir ◽  
Nor Roslina Rosli ◽  
Farid Mulana
Keyword(s):  
Moisture Content ◽  
Drying Kinetics ◽  
Drying Rate ◽  
Airflow Rate ◽  
Drying Process ◽  
Air Velocity ◽  
Mango Fruit ◽  
Drying Time ◽  
Different Temperatures ◽  
Kinetics Of

Drying is generally used to increase the shelf life of food products. In this context, mango fruit is used as a sample for the drying process because of its high commercial value and particularly high moisture content. The mango was sliced into few batches of sample with a size of 20 mm × 30 mm × 5 mm each. The experiments were conducted using tray and oven dryer at different temperatures of 40, 50 and 60 °C with a steady airflow rate of 1.3 m/s. The objectives are to study the effect of drying time, temperature and air velocity towards drying of mango fruit, to compare the physical characteristics of mango sample after drying and to determine the best drying kinetics model fitted to each tray and oven dryer. The results showed that the increase in drying time, temperature and air velocity would reduce the moisture content while at the same time, drying rate increased significantly. Tray dryer was found to be more effective than oven dryer because of higher drying rate with better product quality and appearance at the end. Furthermore, the gathered data were fitted into few widely used drying mathematical models and it was found that Henderson and Pabis model at 60°C is best suited for tray dryer whereas Page model at 40 °C is the best for oven dryer.

scholarly journals Investigation of Selected Utility Properties of Woven Fabrics Made of Soybean Protein Fibres

2019 ◽  
Vol 27 (6(138)) ◽  
pp. 39-45 ◽  
Author(s):  
Małgorzata Matusiak ◽  
Dominika Kamińska
Keyword(s):  
Mechanical Properties ◽  
Water Vapour ◽  
Moisture Transport ◽  
Soybean Protein ◽  
Good Alternative ◽  
Woven Fabrics ◽  
Utility Value ◽  
Renewable Sources ◽  
Vapour Permeability

Soybean Protein Fibres (SPF) are man-made fibres manufactured from the proteins contained in soybeans. They are biodegradable fibres derived from renewable sources, friendly for people and the environment. Within the framework of the work presented, selected utility properties of fabrics containing SPFs were investigated. The scope of the investigation included determination of mechanical properties, drapeability, water-vapour permeability and liquid moisture transport. The investigations carried out allowed to evaluate the utility value of fabrics made with the use of SPFs and to compare the fabric 100% made of SPFs with ones with weft yarns other than from SPFs. The research showed that fabrics with SPFs are suitable for clothing products, which may be a very good alternative to the currently available clothing made from fabrics containing standard natural and chemical fibres.

Hybrid response surface methodology–artificial neural network optimization of drying process of banana slices in a forced convective dryer

2017 ◽  
Vol 24 (4) ◽  
pp. 277-291 ◽  
Author(s):  
Amin Taheri-Garavand ◽  
Fatemeh Karimi ◽  
Mahmoud Karimi ◽  
Valiullah Lotfi ◽  
Golmohammad Khoobbakht
Keyword(s):  
Neural Network ◽  
Energy Efficiency ◽  
Artificial Neural Network ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Drying Rate ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Artificial Neural

The aim of the study is to fit models for predicting surfaces using the response surface methodology and the artificial neural network to optimize for obtaining the maximum acceptability using desirability functions methodology in a hot air drying process of banana slices. The drying air temperature, air velocity, and drying time were chosen as independent factors and moisture content, drying rate, energy efficiency, and exergy efficiency were dependent variables or responses in the mentioned drying process. A rotatable central composite design as an adequate method was used to develop models for the responses in the response surface methodology. Moreover, isoresponse contour plots were useful to predict the results by performing only a limited set of experiments. The optimum operating conditions obtained from the artificial neural network models were moisture content 0.14 g/g, drying rate 1.03 g water/g h, energy efficiency 0.61, and exergy efficiency 0.91, when the air temperature, air velocity, and drying time values were equal to −0.42 (74.2 ℃), 1.00 (1.50 m/s), and −0.17 (2.50 h) in the coded units, respectively.

scholarly journals PADDY DRYING IN MIXED ADSORPTION DRYER WITH ZEOLITE: DRYING RATE AND TIME ESTIMATION

REAKTOR ◽  
2013 ◽  
Vol 14 (3) ◽  
pp. 173 ◽  
Author(s):  
Mochammad Djaeni ◽  
Dewi Ayuningtyas ◽  
Nurul Asiah ◽  
Hargono Hargono ◽  
Ratnawati Ratnawati ◽  
...  
Keyword(s):  
Time Estimation ◽  
Drying Rate ◽  
Air Velocity ◽  
Medium Temperature ◽  
Drying Time ◽  
Fluidized Bed Dryer ◽  
Quality Degradation ◽  
Operational Temperature ◽  
Unpleasant Odor ◽  
Speed Up

Recently, the main problem of the rice stock and distribution in Indonesia is the quality degradation as indicated in unpleasant odor (smelly), stained, yellowness, and high percentage of broken rice. This is due to the low of paddy quality dried by from either direct sunlight or conventional fluidized bed dryer. As a result, the paddy cracks and breaks easily during milling in which causes the storage life being shorter as the enzymatic degradation by germ or fungi occurs. Air dehumidified with zeolite at drying medium temperature is potential to improve the quality of paddy. Zeolite is a material having high affinity to water vapor. In this case, the paddy and zeolite was mixed and fluidized with the air. The air will evaporate water from paddy, and at same time, the zeolite will adsorb water from air. Hence, the humidity of dryer can be kept low in which improves the driving force for drying. This work discusses the effect of presence of zeolite in the dryer, operational drying temperature, air velocity and relative humidity on drying rate of paddy. The results showed that increasing of zeolite as well as operational temperature increased the drying rate. In addition, using the model, the air dehumidification with zeolite and increase of air velocity can speed up drying time significantly at operational temperature below 80oC. This condition is very suitable for paddy drying since the quality degradation can be avoided.

scholarly journals Determination of Sliced Pineapple Drying Characteristics in A Closed Loop Heat Pump Assisted Drying System

2018 ◽  
Vol 7 (1) ◽  
pp. 35 ◽  
Author(s):  
Cüneyt Tunçkal ◽  
Salih Coşkun ◽  
İbrahim Doymaz ◽  
Ernes Ergun
Keyword(s):  
Heat Pump ◽  
Closed Loop ◽  
Type Equation ◽  
Drying Rate ◽  
Diffusivity Coefficient ◽  
Axial Fan ◽  
Drying Time ◽  
Drying Characteristics ◽  
Drying System

Pineapple (Ananascomosus) slices were dried with the aid of a heat pump assisted dryer (HPD). During this process, air velocity was kept constant at 1m/s, while air temperatures were changed as 37°C, 40°C and 43°C. The drying air was also circulated by using an axial fan in a closed cycle and fresh air was not allowed into the system. The drying rate and drying time were significantly influenced by drying temperature. It was observed that drying temperatures had significant effects on the drying rate and drying time. During the conduct of the study, pineapple slices were dried at 37, 40 and 43°C for 465, 360 and 290 min, respectively. The specific moisture extraction ratio (SMER) values were observed to change as drying temperatures were changed. The drying rate curves indicated that the whole drying process occurred in the falling rate period. Seven well-known thin-layer models (Lewis, Henderson &Pabis, Logarithmic, Page, Midilli & Kucuk, Weibull and Aghbashlo et al.) were employed to make a prediction about drying kinetics through nonlinear regression analysis. The Midilli & Kucuk and Aghbashlo et al. models were consistent with the experimental data. Fick’s second law of diffusion was used to determine the moisture diffusivity coefficient ranging from 3.78×10–9 to 6.57×10-9  m2/s the each of the above mentioned temperatures. The dependence of effective diffusivity coefficient on temperature was defined by means a fan Arrhenius type equation. The activation energy of moisture diffusion was found to be 75.24kJ/mol. Article History: Received: July 18th 2017; Received: October 27th 2017; Accepted: January 16th 2018; Available onlineHow to Cite This Article: Tunçkal, C., Coşkun, S., Doymaz, I. and Ergun, E. (2018) Determination of Sliced Pineapple Drying Characteristics in A Closed Loop Heat Pump Assisted Drying System. International Journal of Renewable Energy Development, 7(1), 35-41.https://doi.org/10.14710/ijred.7.1.35-41

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

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