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Research and simulation fluid dynamic in solar greenhouse dryer

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VIETNAM NATIONAL UNIVERSITY HO CHI MINH CITY HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY * - DUONG HOANG PHI YEN RESEARCH AND SIMULATION FLUID DYNAMIC IN SOLAR GREENHOUSE DRYER Major: Chemical engineering Code: 8520301 MASTER THESIS HO CHI MINH CITY, January - 2022 THIS RESEARCH WAS CONDUCTED AT HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY VNU- HCM Supervisor: Dr Tran Tan Viet Reviewer 1: Assoc Prof Dr Nguyen Tuan Anh Reviewer 2: Assoc Prof Dr Le Anh Kien The master thesis was defended at Ho Chi Minh city University of Technology, VNU-HCM, January 1st, 2022 (Online) The members of Assessment Committee including: Assoc Prof Dr Nguyen Quang Long - Chairman Assoc Prof Dr Nguyen Tuan Anh - Reviewer Assoc Prof Dr Le Anh Kien - Reviewer Dr Pham Thi Hong Phuong - Committee Dr Pham Hoang Huy Phuoc Loi - Secretary Confirmation of the Assessment Committee Chairman and the Head of Faculty after the thesis has been corrected (if any) Assessment Committee Chairman Assoc Prof Dr Nguyen Quang Long Dean of Chemical Engineering Faculty Prof Dr Phan Thanh Son Nam I VIETNAM NATIONAL UNIVERSITY HCM SOCIALIST REPUBLIC OF VIETNAM HO CHI MINH CITY UNIVERSITY OF Independence - Freedom - Happiness TECHNOLOGY MASTER THESIS MISSIONS Date of Birth: 01/01/1996 Place of Birth: Tra Vinh Major: Chemical engineering Code: 8520301 I THESIS TITLE: RESEARCH AND SIMULATION FLUID DYNAMIC IN SOLAR GREENHOUSE DRYER MISSIONS AND CONTENTS: - Investigation of the impact of weather conditions on temperature and humidity distribution inside SGHD by changing a suitable grid by ANSYS Fluent - Investigation of the influence of time on the temperature and humidity distribution inside the SGHD II DATE OF ASSIGNMENT: 22/02/2021 III DATE OF COMPLETION: 05/12/2021 IV SUPERVISORS: Dr Tran Tan Viet SUPERVISORS HEAD OF DEPARTMENT Dr Tran Tan Viet Assoc Prof Dr Le Thi Kim Phung DEAN OF CHEMICAL ENGINEERING FACULTY Prof Dr Phan Thanh Son Nam II ACKNOWLEDGEMENT Each of us has a beautiful youth during my time at the Ho Chi Minh City University of Technology, where youth and enthusiasm are imprinted This university is my home, where I can source knowledge to nurture my passion for learning Also, it was the same place that gave me great friends, teachers, and unforgettable memories First, I would like to express my gratitude and respect to my advisor Dr Tran Tan Viet Thank you for your support, guidance, and encouragement throughout writing my thesis Thank you for creating the best environment for me to study and practice as a solid fulcrum when facing difficulties Thank you for your teachings when I stumble to know that the past does not equal the future Besides, I would like to extend this thanks to my friends Thank you to my best friends (Tony, Bao, Nin, Luon, and Duong) who have always been with me throughout realizing my passion Finally, my best sincere hank goes to my parents, who supported me with this project within the limited time frame Ho Chi Minh City, 18th December 2021 Duong Hoang Phi Yen III ABSTRACT This study investigates the internal conditions of the solar greenhouse dryer with drying agricultural products The operating conditions inside the solar greenhouse dryer were analyzed by ANSYS Fluent software using mathematical models Additionally, the moist air outside changed according to the climatic conditions of the day Specifically, moist air enters the dryer through two front doors and exits through three exhaust fans installed in the back, and the flow was considered unstable and tumultuous Agricultural products inside the solar greenhouse dryer were modeled as a porous material, and the radiation was modeled according to the radiation model The simulation results show the distribution of temperature and humidity inside the solar drying greenhouse by the influence of heat exchange, turbulent flow, and the process of removing moisture from the drying material to the outside The simulation results show that indoor drying temperature ranges from 303.15 K to 323.1 K at each time from 7:00 AM to 6:00 PM The drying house reached its highest temperature at 2:00 PM Variations of relative humidity in GHSD are between 23.70% and 79.55% The airflow velocity inside the drying house is almost independent of time and varies based on location In addition, the numerical simulation for solar greenhouse dryer performance The numerical simulations compared the meshing strategies for the dryer and showed the effects on both temperature distribution and relative humidity distribution of air inside the dryer Unstructured meshes were used in the numerical simulation employing hexahedral meshing and tetrahedral meshing for mesh generation The meshing strategies were evaluated through sizes of cells, i.e., 0.1 m and 0.05m The results indicated that the cell size has a stronger effect than the mesh type on the temperature profile and humidity of the air inside the dryer Thus, the results gave the engineers more options to select the optimum meshing conditions and simulate the dryer IV TÓM T T Lu s d ng ph n m m mô ph mô t phân b nhi m v v n t c c a d ng không kh m bên nh s t t i t nh An Giang ng Tháp v i t ng m c tiêu khác (các thông s kh gian s ng c ng m t tr i i nhi t, dòng ch y r m i th m t gi S s ng t n 323,1 K t i t nhi cao nh t lúc gi chi u i nhà s y t gió bên nhà s y h ng c a trình m t v t li u s y bên K t n gi t i Nhà s ic i theo th i i) K t qu mô ph ng cho th y s phân b nhi t m bên nhà kính s qu mơ ph ng cho th y nhi n 79,55% V n t c lu ng thu c vào th i tùy theo v trí Ngồi ra, mơ ph ng s cho hi u su t c a thi t b s y nhà kính b Bên c o sát s nhi phân b c it i khơng có i l c di i phù h i t di n c c a ô, t c 0,1 m c có m c a khơng khí bên máy s u ki ng lên c phân b i c a khơng khí bên Các m 0,05m K t qu ch r nhi ng m t tr i i cho nhà s y cho th c s d ng mô ph ng s s d L a ch , ng nhà s y ng m i lo t qu n hi c V DECLARATION I hereby declare that the thesis has been composed by myself and that the work has not to be submitted for any other degree or professional qualification I confirm that the work submitted is my own, except where work formed part of jointly authored publications has been included My contribution and those of the other authors to this work have been explicitly indicated below Finally, I confirm that appropriate credit has been given within this thesis where reference has been made to the work of others Part of the work presented in this thesis was my publication, which was previously published in Scientific Reports, Chemical Engineering Transaction, and the IOP conference journal Chemical Engineering Transaction as Three-Dimetional of Simulation of The The Author Duong Hoang Phi Yen VI TABLE OF CONTENTS MASTER THESIS MISSIONS I ACKNOWLEDGEMENT II ABSTRACT III TÓM T T IV DECLARATION V TABLE OF CONTENTS VI LIST OF FIGURES IX LIST OF TABLES XI PREFACE 1.1 Rationale 1.2 Research aims and Objectives .3 1.3 Outline of thesis .3 LITERATURE REVIEW 2.1 Solar drying process overview .4 2.1.1 Solar drying 2.1.2 Classification of drying methods using solar energy .5 2.1.3 Various shapes of the SGHD 2.2 Introduction to computational fluid dynamic (CFD) simulation 2.2.1 ANSYS Fluent 2.2.2 Working principle of ANSYS CFD MATHEMATICAL MODELS 12 3.1 Conservation equations [20] 12 3.1.1 Mass conservation: .12 3.1.2 Momentum conservation .12 VII 3.1.3 Energy conservation .13 3.1.4 Heat and mass balances in SGHD: 14 3.2 Viscous Model [20] .18 3.2.1 Standard k3.2.2 Realizable k- 18 19 3.3 Species model [16] 21 3.3.1 Mass diffusion in turbulent flow 21 3.3.2 Treatment of Species Transport in the Energy Equation .22 3.4 Radiation model [20] 22 SIMULATION OF SOLAR GREENHOUSE DRYER 24 4.1 Bench-scale of solar greenhouse dryer 24 4.1.1 Geometry 24 4.1.2 Geometrical discretization [20] 25 4.1.3 Physical properties and boundary conditions 26 4.1.4 Simulation method and the operating conditions 27 RESULTS AND DISCUSSION 29 5.1 Profile temperature and relative humidity inside the SGHD .29 5.1.1 The distribution of temperature .30 5.1.2 The distribution of relative humidity .33 5.2 The sensitive mesh .35 5.3 Mesh quality 38 5.3.1 Influence of number of cells on the simulated results 41 5.3.2 Influent of mesh type on the simulated results 43 CONCLUSION 48 LIST OF PUBLICATION .49 VIII REFERENCES 50 SHORT CURRICULUM VITAE 52 38 (d) Figure 17 Mesh distribution of SGHD for different mesh grid types: (a) hexahedral mesh H01, (b) hexahedral mesh H005, (c) tetrahedral mesh T01, and (d) tetrahedral mesh T005 In Figure 9, the grid distributions of hexahedral and tetrahedral mesh types had similar However, the distribution with different sizes of cell investigation defined the large mesh dimension used in the main flow region as the global mesh dimension 5.3 Mesh quality In this study, unstructured mesh and structured mesh were combined As mentioned before, the unstructured grid can lead to a high cost during the computation Hence structured mesh accounted for most of this model The quality standard of the mesh is illustrated in Figure 20 Figure 18 and Figure 19 show the orthogonality and skewness values of the parameters related to mesh quality Both orthogonality and skewness values go from to On the one hand, if the value of orthogonality is near 0, the mesh has low quality On the other hand, the values near correspond to a high quality in the skewness case Skewness is defined as the difference between the shape of the cell and an equilateral cell of equivalent volume Figure 18 and Figure 19 (a) and (c) show the orthogonal quality and skewness of hexahedral mesh H01, H005 with the distribution of highest the number of elements in 39 the region are 0.95 and over 0.06, respectively With the tetrahedral (b) T01 and (c) T005 mesh model, the orthogonal quality results with the highest number of elements in the region is 0.5 and 0.44 0.06, respectively Based on the standard quality of mesh in Figure 20, the results show that the hexahedral mesh has excellent quality and is favorable for this model than the tetrahedral mesh The results are as good as the hexahedral mesh, ensuring that the mesh is essential to producing reliable and accurate results (a) (b) (c) (d) 40 Figure 18 The orthogonal quality mesh (a) hexahedral mesh H01, (b) tetrahedral mesh T01, (c) hexahedral mesh H005 and (d) tetrahedral mesh T005 (a) (b) (c) (d) 41 Figure 19 The skewness of mesh (a) hexahedral mesh H01, (b) tetrahedral mesh T01, (c) hexahedral mesh H005 and (d) tetrahedral mesh T005 Figure 20 The skewness and orthogonal mesh quality (2015 ANSYS, Inc.) 5.3.1 Influence of number of cells on the simulated results Modeling internal conditions in solar dryers is the key factor in investigating dryer efficiency The internal conditions of SGHD depended on the location and the time Besides temperature, the velocity vector of the airflow is one of the essential factor effects on the properties of the dryer Figure 21 compares the simulated temperature profiles and the velocity vector of the air inside SGHD at 10 AM with tetrahedral meshes of different cell numbers from 905,709 cells to 7,179,729 cells When the number of cells was increased, the predicted air temperature distributions agreed well with the measured distribution (a) 42 (b) (c) (d) 43 Figure 21 Temperature distribution and velocity of air inside SGHD at 10 AM for different mesh grid sizes: (a) and (c): tetrahedral mesh T01, (b) and (d) tetrahedral mesh T005 The roof and dryer absorbed the solar radiation from morning to afternoon and were heated due to the greenhouse effect This figure shows the strong relation of solar irradiation through the polycarbonate wall on the temperature distribution To investigate the effects of grids number on the temperature simulation, the average temperature and maximum air temperature inside SGHD for different mesh grid sizes 60 100 50 80 40 30 20 T01 10 T005 TEMPERATURE (C) TEMPERATURE (C) were conducted and shown in Figure 22 60 40 T01 20 T005 TIME (a) TIME (b) Figure 22 Comparison of the average temperature profiles (a) and the maximum temperature profiles (b) computed using different tetrahedral meshes The simulation results implied that the different grid numbers led to different temperature simulated results As a result, the average temperature distribution results were very similar, and the error value was less than 5% However, the simulation results of the maximum temperature inside the dryer were different from those with finer grids Hence, a further increase in grid number influenced the simulated temperature profiles 5.3.2 Influent of mesh type on the simulated results The simulated temperature distributions and the temperature volume rendering of the air inside the SGHD using hexahedral mesh type with two sizes of the cell are shown in Figure 23, and the comparison of the average temperature and the maximum temperature of the air inside SGHD using different mesh type is shown in Figure 24 44 (a) (b) (c) 45 (d) Figure 23 Temperature distribution and the temperature volume rendering of air inside SGHD at 10 AM using hexahedral mesh type, (a) and (c): hexahedral mesh H01, (b) and (d): hexahedral mesh H005 50 40 30 20 T01 H01 10 TIME (a) TEMPERATURE (C) TEMPERATURE (C) 60 80 70 60 50 40 30 20 10 T01 H01 TIME (b) Figure 24 Comparison of the average temperature profiles (a) and the maximum temperature profiles (b) computed using hexahedral mesh type T01 and tetrahedral mesh type H01 In this research, when the size of the cell is similar, the number of cells by using tetrahedral mesh type was more than times the number of cells by using hexahedral mesh type In Figure 24 and Figure 25, the result of temperature distribution of air in the SGHD using the hexahedral grid had a higher accuracy than the result which was used the tetrahedral grid, and at sufficiently high grid numbers, the effect of mesh type on the simulation results was small In Figure 24, the different value of average temperature profiles was not significant, and the maximum air temperature of the air in the SGHD 46 of hexahedral mesh type was normally lower than the maximum air temperature of the air in the SGHD hexahedral mesh type Further, the influence of mesh type on the relative humidity of the air inside the GHSD was investigated The humidity of moist air inside the SGHD differs widely in space and depends on time The simulation results with various mesh types are illustrated in Figure 25 (a) (b) Figure 25 Relative humidity distribution of air inside SGHD at 10 AM using tetrahedral mesh type T01 (a) and hexahedral mesh H01 (b) Relative humidity decreases with time inside the dryer from sunrise to sunset This was caused by decreasing relative humidity of the ambient air and increased water holding capacity of the drying air due to temperature increase The comparison of the relative humidity simulation result using hexahedral mesh type and tetrahedral mesh type is present in Figure 26 47 RELATIVE HUMIDITY (%) 90 80 T01 H01 70 60 50 40 30 20 10 TIME Figure 26 Comparison of the relative humidity computed using hexahedral mesh type (H01) and tetrahedral mesh type (T01) With the same cell size, the relative humidity simulation computed using hexahedral mesh type (T01) was very similar to the result using tetrahedral mesh type The error value of relative humidity computed between hexahedral and tetrahedral mesh types was very small The profile RH values could be interpreted clearly by the temperature distribution of moist air in the volume of GHSD in Figure 24 The air inside the dryer decreases from day to night, but the relative humidity of the air inside the dryers was always lower than that of the ambient air The computing time of experiments strongly depended on the number of cells and the node numbers of the cells In this research, the computing time was nearly proportional to the grid number, and the hexahedral meshes took the longest computing time 48 CONCLUSION This thesis created a computational model of SGHD in SpaceClaim with simulation using ANSYS Fluent The results indicate the complex models in which 3D geometry is favorable for predicting the dryer's performance with several incident solar radiations in various weather conditions The temperature distribution and the velocity of moist air inside the dryer from sunrise to sunset have been simulated Additionally, numerically obtained results are consistent with experimental results The highest temperature and lowest RH at 2:00 PM are 66.1°C (339 K) and 23.70% Moreover, the velocity distribution of the air is more uniform The simulation results also present the relation of RH inside the dryer at the location and time at which the maximum value of RH is 79.55%, and the minimum value is 23.70% The results of the simulation distribution temperature and distribution RH prove that the SGHD could be operated throughout an entire day and can be a prime for building dryers in agricultural countries CFD simulation simulated and predicted the temperature and air flow distribution inside the GSHD for various possible operating conditions This study evaluated the performance of two mesh types of combination with two sizes of cells for predicting airflow and temperature distributions in the GSHD The result proves that the hexahedral and tetrahedral mesh type has the same result of airflow distribution inside the GSHD simulation Therefore, increasing the number of cells was the best method to improve the accuracy and efficiency of GSHD simulations 49 LIST OF PUBLICATION N T Vo, P T K Le, V T Tran, Three-Dimensional Simulation of Solar Greenhouse Dryer, Chemical Engineering Transactions, vol 3, pp 211-216, 2021 V T Tran, T M Le, The Influence of Meshing Strategies on The Numerical Simulation of Solar Greenhouse Dryer, IOP Conference Series: Earth and Environmental Science, vol 947, pp 012007, 2021 N T Vo, T M Le, K D Ta, P K Le, V T Tran, Novel Process Simulation of Biodiesel Production from Crude Castor Oil, Chemical Engineering Transactions, vol 83, pp 295-300, 2020 T M Le, U P N Tran, Q D Nguyen, V T Tran, P T Mai, P K Le, Sustainable bioethanol and value-added chemicals production from paddy residues at pilot scale Clean Technologies and Environmental policy, vol 20, 2021 T M Le, U P N Tran, K T Nguyen, V T Tran, P K Le, Development of a paddy-based biorefinery approach toward improvement of biomass utilization for more bioproducts, 133-249, 2021 Chemosphere, vol 289, pp 50 REFERENCES [1] A Rahman et al "A case study of thermal analysis of a solar assisted absorption air-conditioning system using R-410A for domestic applications," Case Studies in Thermal Engineering, vol 26, pp 101008, 2021 [2] H Wang et al "Comparison of three new drying methods for drying characteristics and quality of shiitake mushroom (Lentinus edodes)," Drying Technology, vol 32, pp 1791-1802, 2014 [3] P Singh et al "Performance evaluation of evacuated solar collector assisted hybrid greenhouse solar dryer under active and passive mode," Materials Today: Proceedings, vol 5, pp 35-40, 2021 [4] R O Lamidi et al "Recent advances in sustainable drying of agricultural produce: A review," Applied Energy, vol 233, pp 367-385, 2019 [5] M Picón-Núđez et al "Thermo-hydraulic design of solar collector networks for industrial applications," Chemical Engineering Transactions, vol 35, pp 457-462, 2013 [6] N I Román Roldán et al "Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer chapel type coupled to an air solar heating system," Energy Science & Engineering, vol 7, pp 1123-1139, 2019 [7] Y H Duong et al "Three-Dimensional Simulation of Solar Greenhouse Dryer," Chemical Engineering Transactions, vol 83, pp 211-216, 2021 [8] V T Tran et al., IOP Conference Series: Earth and Environmental Science, vol 947, pp 012007, 2021 [9] Z Admass Mathematical modelling and exxperimental testing of mixed mode solar drying system for red pepper Dotoral thesis, University of Cincinnati, USA, 2020 [10] A Sharma et al "Solar-energy drying systems: A review," Renewable and Sustainable Energy Reviews, vol 13, pp 1185-1210, 2009 [11] H G Mobtaker et al "Simulation of thermal performance of solar greenhouse in north-west of Iran: an experimental validation," Renewable Energy, vol 135, pp 88-97, 2019 51 [12] U et al "Using solar greenhouses in cold climates and evaluating optimum type according to sizing, position and location: A case study." Computers and Electronics in Agriculture, vol 117, pp 245-257, 2015 [13] M Vivekanandan et al "Experimental and CFD investigation of six shapes of solar greenhouse dryer in no load conditions to identify the ideal shape of dryer," Materials Today: Proceedings, vol 37, pp 1409-1416, 2021 [14] H K Versteeg and W Malalasekera, An introduction to computational fluid dynamics: the finite volume method Pearson education, USA, 2009 [15] I J I Ansys, "Ansys," Southpointe, vol 275, pp 150-200, 2017 [16] V N Fernando et al Bio-Inspired Aircraft Wing Modification Analysis in ANSYS Fluent 10th International Conference on Information and Automation for Sustainability (ICIAfS), IEEE, vol 10, pp 316-321, 2021 [17] J G Heywood et al "Finite-element approximation of the nonstationary Navier Stokes problem Part IV: Error analysis for second-order time discretization," SIAM Journal on Numerical Analysis, vol 27, pp 353-384, 1990 [18] A Sarshar et al "A numerical investigation of matrix-free implicit timestepping methods for large CFD simulations," Computers & Fluids, vol 159, pp 53-63, 2017 [19] P I Muiruri et al "Three Dimensional CFD Simulations of A Wind Turbine Blade Section; Validation," Journal of Engineering Science & Technology Review, vol 11, pp 1-30, 2018 [20] A J A Fluent, ANSYS fluent theory guide 15.0 Canonsburg, PA : Ansys, 2013 [21] S Janjai et al "Experimental and simulated performance of a PV-ventilated solar greenhouse dryer for drying of peeled longan and banana," Solar Energy, vol 83, pp 1550-1565, 2009 [22] S Gorjian et al "Recent Advancements in Technical Design and Thermal Performance Enhancement of Solar Greenhouse Dryers." Sustainability, vol 13, pp 25-70, 2021 52 SHORT CURRICULUM VITAE Personal information Full name: DUONG HOANG PHI YEN Sex: female Date of birth: 1/1/1996 Place of birth: Tra Vinh Phone: 097 171 232 Email: dhpyen.sdh20@hcmut.edu.vn Working address: 268 Ly Thuong Kiet St., Ward 14, District 10, Ho Chi Minh City, Vietnam Education profile a Undergraduate (2015 2020) Graduated from: Ho Chi Minh City University of Technology Vietnam National University Major: Chemical Engineering Mode of study: Full time Degree classification: Good b Post-graduate (2020 present) Currently studying Master program at Ho Chi Minh City University of Technology Vietnam National University Major of Chemical Engineering Working experience 02/2020 present: Research Engineer at Refinery & Petrochemicals Technology Research Centre, Ho Chi Minh City University of Technology University Vietnam National ... TITLE: RESEARCH AND SIMULATION FLUID DYNAMIC IN SOLAR GREENHOUSE DRYER MISSIONS AND CONTENTS: - Investigation of the impact of weather conditions on temperature and humidity distribution inside... solve engineering problems in various industries, including aerodynamics of aircraft and vehicles, hydrodynamics of ships, power plants, turbomachinery, electrical and electronic engineering, chemical... discussion in Chapter and conclusions in Chapter 4 LITERATURE REVIEW 2.1 Solar drying process overview 2.1.1 Solar drying The greenhouse effect can explain collecting heat from the sun of solar drying
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