On the Use of CFD in Thermal Analysis of Industrial Hollow Ceramic Brick

2017 ◽  
Vol 10 ◽  
pp. 70-82 ◽  
Author(s):  
Morgana Vasconcellos Araújo ◽  
J.M.P.Q. Delgado ◽  
A.G. Barbosa de Lima
Keyword(s):  
High Energy ◽  
Process Time ◽  
Turbulent Regime ◽  
Drying Process ◽  
Air Velocity ◽  
Clay Bricks ◽  
Hot Air ◽  
Transient Thermal ◽  
Time And Energy ◽  
High Energy Consumption

The manufacture of clay bricks goes through several phases, among which are clay wetting, molding, drying and firing. The drying process has a high energy consumption and the material needs to be dried with control for avoid it to be unusable after drying. Optimization of the drying process (reduction of process time and energy expenditure) is crucial for the ceramist industry. In this sense, this work aims to make a transient thermal study of the temperature distribution in an industrial brick due to the energy supply of drying-air flowing inner it turbulent regime. The study is performed through numerical simulation using the software ANSYS® CFX. Transient results are displayed in terms of fields of the temperature and air velocity, and temperature of the brick. It was concluded that the higher the velocity of flow of hot air, the faster the heat diffuses into the brick. Independent of air velocity, there are temperature gradients on the surface of the brick

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 Optimisation of energy consumption of a solar-electric dryer during hot air drying of tomato slices

2019 ◽  
Vol 50 (3) ◽  
pp. 150-158 ◽  
Author(s):  
Nnaemeka R. Nwakuba
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
High Energy ◽  
Slice Thickness ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Drying Conditions ◽  
Desirability Index

High-energy demand of convective crop dryers has prompted study on optimisation of dryer energy consumption for optimal and cost effective drying operation. This paper presents response surface optimisation of energy consumption of a solar-electric dryer during hot air drying of tomato slices. Drying experiments were conducted with 1 kg batch of tomato samples using a 33 central composite design of Design Expert 7.0 Statistical Package. Three levels of air velocity (1.0, 1.5 and 2.0 ms–1), slice thickness (10, 15 and 20 mm) and air temperature (50, 60 and 70°C) were used to investigate their effects on energy consumption. A quadratic model was obtained with a high coefficient of determination (R2) of 0.9825. The model was validated using the statistical analysis of the experimental parameters and normal probability plot of the energy consumption residuals. Results obtained indicate that the process parameters had significant quadratic effects (P<0.05) on the energy consumption. The energy consumption varied between 5.42 kWh and 99.78 kWh; whereas the specific energy consumption varied between 5.53 kWhkg–1 and 150.61 kWhkg–1. The desirability index method was applied in predicting the ideal energy consumption and drying conditions for tomato slices in a solar-electric dryer. At optimum drying conditions of 1.94 ms–1 air velocity, 10.36 mm slice thickness and 68.4°C drying air temperature, the corresponding energy consumption was 5.6 8kWh for maximum desirability index of 0.989. Thermal utilisation efficiency (TUE) of the sliced tomato samples ranged between 15 ≤TUE ≤58%. The maximum TUE value was obtained at 70°C air temperature, 1.0 ms–1 air velocity and 10 mm slice thickness treatment combination, whereas the minimum TUE was obtained at 50°C air temperature, 2.0 ms–1 air velocity and 20 mm slice thickness. Recommendation and prospect for further improvement of the dryer system were stated.

scholarly journals Application of Infrared Heating for Roasting Nuts

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Hadi Bagheri
Keyword(s):  
Energy Consumption ◽  
Production Efficiency ◽  
High Energy ◽  
Quality Characteristics ◽  
Infrared Heating ◽  
Ir Radiation ◽  
Thermal Methods ◽  
Hot Air ◽  
A New Technique ◽  
Time And Energy

Roasting is a key process in production of nuts. Improving the flavor and crispiness of texture in nuts is considered as a purpose of roasting, which increases the overall acceptance of the product. This review aims to introduce the infrared method as a new technique of roasting and evaluate the quality characteristics of some nuts after infrared roasting. Usually, the traditional roasting methods are time-consuming with high energy consumption and low production efficiency. One of the best ways to decrease roasting time and energy consumption is to provide heat by infrared (IR) radiation. However, the low penetration power of infrared radiation is one of the limitations of this method. The combination of infrared with other thermal methods can overcome this limitation. Studies have been done on roasting of nuts and other foods by different IR roasting methods such as IR, IR-hot air, and IR-microwave roasting methods. This paper reviews the effect of different IR roasting methods on the quality characteristics of roasted pistachio, peanut, hazelnut, almond, sunflower, soybean, and other food products. IR heating has been applied successfully to the roasting of some nuts. The use of infrared roasting has several advantages in comparison with traditional convective roasting methods. According to the results of most of these studies, the combination of infrared with other thermal methods to roast nuts has distinctly improved the potential of the technology as compared to the IR roasting alone.

scholarly journals Estimation of the Energy Consumption of the Rice and Corn Drying Process in the Equatorial Zone

2020 ◽  
Vol 10 (21) ◽  
pp. 7497
Author(s):  
Emérita Delgado-Plaza ◽  
Miguel Quilambaqui ◽  
Juan Peralta-Jaramillo ◽  
Hector Apolo ◽  
Borja Velázquez-Martí
Keyword(s):  
Energy Consumption ◽  
Agricultural Sector ◽  
High Energy ◽  
Productivity Index ◽  
Industrial Processes ◽  
Liquefied Petroleum Gas ◽  
Drying Process ◽  
Yellow Corn ◽  
Marketing Chain ◽  
High Energy Consumption

Drying is considered one of the industrial processes that requires more energy than other processes, being a topic of much interest to the agricultural sector, especially the evaluation of energy consumption for rice and corn dryers. To meet this goal, an overview survey matrix and protocols for temperature measurements of dryers were developed. The study evaluated 49 rice dryers and 14 yellow corn dryers. As a result, it was determined that the oversizing of the fan/extractor and the dryer engine generates a high energy consumption, added to the lack of insulation in the heat ducts. Therefore, the drying productivity index is very low in dryers using liquefied petroleum gas (LPG) being 0.14 dollar/quintal for rice and 0.27 dollar/quintal for corn and using biomass reaches 1.4 dollars/quintal. In relation to energy losses, these account for more than 55%. Inadequate energy management in drying processes directly influences the marketing chain of products, the losses of which are caused by fluctuations in the price of rice and corn on the domestic market, with the agricultural sector having to generate an energy efficiency plan.

scholarly journals Kinetic parameters identification of conductive enhanced hot air drying process of food waste

2020 ◽  
pp. 223-223
Author(s):  
Mihailo Milanovic ◽  
Mirko Komatina ◽  
Ivan Zlatanovic ◽  
Nebojsa Manic ◽  
Dragi Antonijevic
Keyword(s):  
Food Industry ◽  
Convective Drying ◽  
Diffusivity Coefficient ◽  
Drying Method ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Curves

The efficient utilization of waste from food industry is possible after thermal treatment of the material. This treatment should be economically feasible and compromise the energy efficient drying process. The main goal of this investigation is to determine drying characteristics of nectarine pomace as a waste from food industry. The measurements were performed in an experimental dryer by combined conductive-convective drying method with disk-shaped samples of 5, 7 and 10mm thickness and 100 mm in diameter at the air temperatures of 30, 40, 50, 60 and 70oC, hot plate temperatures of 50, 60 an 70oC and air velocity of 1.5 m/s. The drying curves were compared to a few semi-theoretical mathematical models. The Logarithmic model showed the best correspondence. On the basis of experiments, it is determined that the drying process takes place in a falling rate period and it is accepted that the main mechanism of moisture removal is diffusion. The effective coefficient of diffusion was determined using experimental results by calculating the slope of the drying curves. Drying time and equilibrium moisture are determined for each experiment. Analysis of drying curves showed that the conductive-enhanced drying method reduces drying times and increases the diffusivity coefficient. The character of drying rate curves for conductive-enhanced drying was analyzed and compared with pure convective drying of nectarine pomace.

scholarly journals RESEARCH OF PLUM DRYING PROCESS

2015 ◽  
Vol 3 ◽  
pp. 494-5 ◽  
Author(s):  
Nurlan Kurmanov ◽  
Azret Shingissov ◽  
Gulzhan Kantureyeva ◽  
Zeinep Nurseitova ◽  
Baurzhan Tolysbaev ◽  
...  
Keyword(s):  
Acid Content ◽  
Ascorbic Acid Content ◽  
Drying Method ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air ◽  
Sensory Parameters ◽  
Air Dryer ◽  
Kinetics Of

In this study, the drying kinetics of a domestic plum cultivar were examined in a laboratory scale hot-air dryer, SHS-80, at an air velocity of 0.65m s-1 and within the air temperature range of 45 – 75 0С. It was found that the whole fruit dried the best. Also, the study  assessed the influence of the drying method on the quality of the domestic plum cultivar. Dried fruits were assessed for sensory parameters and ascorbic acid content. Studies have shown thatthe proposed method of drying, yields a higher absorbic acid content for the dried product  than the conventional approach.

scholarly journals Dynamics of convective hot air drying of filiform Lagenaria siceraria

2013 ◽  
Vol 19 (4) ◽  
pp. 485-492 ◽  
Author(s):  
Aishi Zhu ◽  
Kai Xia
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer Coefficient ◽  
Lagenaria Siceraria ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Temperature ◽  
Hot Air

In this study, a laboratory convective hot air dryer was used for the thin-layer drying of filiform Lagenaria siceraria and the influences of the drying temperature and air velocity on the drying process were investigated. The drying temperature and the air velocity were varied in the range of 60-80?C and 0.6-1.04 m?s-1, respectively. The experimental data of moisture ratio of filiform Lagenaria siceraria were used to fit the mathematical models, and the dynamics parameters such as convective heat transfer coefficient ? and mass transfer coefficient kH were calculated. The results showed that the drying temperature and air velocity influenced the drying process significantly. The Logarithmic model showed the best fit to experimental drying data. It was also found that, the air velocity and the drying temperature influence notable on both of the convective heat transfer coefficient ? and the mass transfer coefficient kH. With the increase of hot air velocity from 0.423 to 1.120 ms-1, the values of ? varied from 111.3 to 157.7 W?m-2?K-1, the values of kH varied from 13.12 to 18.58 g?m-2? s-1??H-1. With the increase of air temperature from 60 to 80?C, the values of ? varied between 150.2 and 156.9 W?m-2?K-1, the values of kH varied between 18.26 and 18.75 g?m-2?s-1??H-1.

Drying of Ceramic Bricks: Thermal and Mass Analysis via CFD

2020 ◽  
Vol 25 ◽  
pp. 133-153 ◽  
Author(s):  
R.S. Santos ◽  
Severino Rodrigues de Farias Neto ◽  
A.G. Barbosa de Lima ◽  
J.B. Silva Júnior ◽  
A.M. Vasconcelos da Silva
Keyword(s):  
Moisture Content ◽  
Low Cost ◽  
Ceramic Materials ◽  
High Energy ◽  
Average Moisture Content ◽  
Air Velocity ◽  
Operational Conditions ◽  
Computational Fluid Dynamics Analysis ◽  
High Energy Consumption ◽  
Good Agreement

Several studies about drying of ceramic materials have been developed in many engineering and fabrication sectors. This process requires high investments and high energy consumption, resulting in high costs to the companies of this sector. In many situations, it is common the use of theoretical solutions that allow, with relative ease and low cost, to change the operational and geometrical conditions of the dryer or object of drying, to obtain the optimized operational conditions. In this sense, this work aims to predict the drying process of a ceramic brick in an oven using the computational fluid dynamics analysis. For a drying temperature of 80°C, the results of the drying and heating kinetics, and the moisture content and temperature distributions of the product and the air and the air velocity and pressure in the oven are shown and analyzed. A comparison between the predicted and experimental data of the average moisture content and temperature of the brick along the process was done and a good agreement was obtained.

scholarly journals Natural Gas Intermittent Kiln for the Ceramic Industry: A Transient Thermal Analysis

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1568 ◽  
Author(s):  
Ricardo S. Gomez ◽  
Túlio R. N. Porto ◽  
Hortência L. F. Magalhães ◽  
Gicelia Moreira ◽  
Anastácia M. M. C. N. André ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Thermal Insulation ◽  
Mathematical Formulation ◽  
High Energy ◽  
Thermal Discomfort ◽  
Heating And Cooling ◽  
High Reduction ◽  
Work Accidents ◽  
Transient Thermal ◽  
Time And Energy

Drying and firing of ceramic products are processes that require high energy consumption. Making these processes more efficient can improve product quality, reduce processing time and energy consumption, and promote economic and environmental gains. In this sense, this work aims to quantify heat transfer in an intermittent ceramic kiln during the heating and cooling stages, with and without thermal insulation. All mathematical formulation is based on the first law of thermodynamics. From the results, we conclude that the greatest heat loss occurs by radiation in the sidewalls of the equipment, and that a considerable amount of energy is required to heat the sidewalls, base, and ceiling of the kiln. Further, with the use of thermal insulation, it was concluded that a high reduction in the heat lost through the sidewalls was achieved, thus providing a global energy gain of approximately 35% and a reduction in the maximum external surface temperature from 249.34 to 79.47 °C when compared to the kiln without thermal insulation, reducing the risks of work accidents and thermal discomfort when in operation.

scholarly journals Bacaba powder produced in spouted bed: an alternative source of bioactive compounds and energy food product

2019 ◽  
Vol 22 ◽  
Author(s):  
Rafael Alves do Nascimento ◽  
Elisângela Lima Andrade ◽  
Elza Brandão Santana ◽  
Nielson Fernando da Paixão Ribeiro ◽  
Cristiane Maria Leal Costa ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Desirability Function ◽  
Food Product ◽  
High Energy ◽  
Simultaneous Optimization ◽  
Drying Process ◽  
Spouted Bed ◽  
Air Velocity ◽  
Alternative Source ◽  
Process Yield

Abstract This study evaluated Bacaba powder produced in a spouted bed as a source of bioactive compounds and high energy value. The conditions influencing the drying process parameters (yield, moisture level, phenolic and anthocyanin retention) as well as simultaneous optimization (optimal conditions) of production were also considered. Drying was most efficient at 75 °C using maltodextrin concentrations above 20.0% (w/w). Higher anthocyanin retention (92.52%) at 65 °C (p = 0.0003), and a maltodextrin concentration of 20.0% (w/w) resulted in high retention of phenolics (95.38%). Accordingly, the operations tested under the desirability function (68 °C, maltodextrin concentration of 21.7% w/w, and air velocity of 1.3 × minimum spouting velocity (Vjm) m s-1) resulted in a process yield of 55.04% and the dry basis (d.b.) composition results were: total phenolics (376.43 mg GAE 100 g-1), energetic value (612.64 kcal 100 g-1), lipids (47.74 g 100 g-1), carbohydrates (27.79 g 100 g-1), protein (15.10 g 100 g-1), and dietetic fiber (8.45 g 100 g-1). The high solubility (92%), flowability (14%), energy, and bioactive characteristics of Bacaba powder suggest the potential for many applications, such as development of dietary supplements, high-energy drinks, milk-based and instant products, and bakery products.

Sign in / Sign up

Export Citation Format

Share Document