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 KAJIAN KENYAMANAN RUANG KULIAH TN II JURUSAN TEKNIK FISIKA UNIVERSITAS GADJAH MADA (UGM) DITINJAU DARI ASPEK TERMAL DAN POLA ALIRAN UDARA MENGGUNAKAN FLUENT

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Sunanto Sunanto ◽  
Karsid Karsid
Keyword(s):  
Temperature Distribution ◽  
Temperature Variation ◽  
Air Temperature ◽  
Geometric Modeling ◽  
Air Flow ◽  
Model Testing ◽  
Velocity Variation ◽  
Air Velocity ◽  
Free Air ◽  
Air Circulation

Temperature and air circulation is an important factor in a building since it is closely related to health comfort. Therefore, the design of a building should be carry out precisely in getting a clean, healthy and comfortable air circulation in accordance to the requirement of the room.In order to carried out a good building designing, a research was needed to understand temperature distribution, the pattern of air flow and its velocity. In this research, a Classroom of TN II JTF UGM. This classroom have 1030 cm length, 790 cm of width, and 330 cm of height. The size of the windows is 100 x 100 cm and place 1m from the floor. The size of the doors is 140 x 210 cm. The windows are assumed to be widely open, the door always opened. The researched begins with geometric modeling of the model by using Gambit 2.2.30 and continued with model testing using Fluent 6.2.16. The test is carried out by giving three velocity variation of free air flowing i.e.: from 1.3 m/s, 3.61 m/s and 5.92 m/s, two direction variation of open air flowing and two variation temperature of free air i.e.: 21.50C and 27.650C.The standard of comfortable air velocity used in the room is 0.15 < V < 0.25 m/s, The standard of comfortable temperature used in the room is 20.50C and 27.10C. The air velocity and air temperature variation created comfort area and non comfort area in the room .The direction circulation of air variation created the different pattern air circulation in the room.

Numerical Study on the Polymer Drawing of the Unsymmetrical Air Flow Field in Melt Blowing Process

2013 ◽  
Vol 796 ◽  
pp. 264-267
Author(s):  
Yao Ma ◽  
Hua Jun Chen ◽  
Ting Chen ◽  
Li Li Wu
Keyword(s):  
Flow Field ◽  
Air Temperature ◽  
Fiber Diameter ◽  
Air Flow ◽  
Transverse Displacement ◽  
Air Velocity ◽  
Melt Blowing ◽  
Air Jets ◽  
Hot Air ◽  
Slot Die

Melt blowing is a typical nonwoven process for producing superfine fibers. In this process, the high velocity hot air jets attenuate the polymer melt into superfine fibers. Therefore, the fiber diameter is strongly affected by the air flow field. Dual slot die is one of the widely used melt blowing dies. Hot air emits from the two slots symmetrically. What will happen to the polymer drawing if the air jets are unsymmetrical? In this paper, the unsymmetrical air flow field of the dual slot die in melt blowing process is simulated numerically. The distributions of air velocity and air temperature are obtained. The polymer drawing model is then solved with the aid of the simulation results of air velocity and air temperature. The diameter and transverse displacement of the threadline along the spinline is achieved. The result shows that the threadline diameter of unsymmetrical air flow field is larger than that of the symmetrical air flow field and the threadline tends to deflect because of the unsymmetrical air jets. This paper helps to indicate the research direction for further decreasing the fiber diameter of melt blown nonwoven fabrics.

scholarly journals Heat Transfer Enhancement in Air Cooled Gas Turbine Blade Using

2021 ◽  
Vol 8 (3) ◽  
pp. 52-69
Author(s):  
Dr. Farhan Lafta Rashid Rashid ◽  
Dr. Haider Nadhom Azziz Azziz ◽  
Dr. Emad Qasem Hussein Hussein
Keyword(s):  
Temperature Distribution ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Air Temperature ◽  
Air Flow ◽  
Three Dimensions ◽  
Internal Diameter ◽  
Wall Surface ◽  
Gas Turbine Blade ◽  
Ansys Fluent

In this paper, an investigation of using corrugated passages instead of circular crosssection passages was achieved in conditions simulate the case in the gas turbine blade coolingusing ANSYS Fluent version (14.5) with Boundary conditions: inlet coolant air temperature of300 K with different air flow Reynolds numbers (191000, 286000 and 382000). Thesurrounding constant hot air temperatures was (1700 K). The numerical simulations was done bysolving the governing equations (Continuity, Reynolds Averaging Navier-stokes and Energyequation) using (k-ε) model in three dimensions by using the FLUENT version (14.5). Thepresent case was simulated by using corrugated passage of 3 m long, internal diameter of 0.3 m,0.01 m groove height and wall thickness of 0.01 m, was compared with circular cross sectionpipe for the same length, diameter and thickness. The temperature, velocity distributioncontours, cooling air temperature distribution, the inner wall surface temperature, and thermalperformance factor at the two passages centerline are presented in this paper. The coolant airtemperature at the corrugated passage centerline was higher than that for circular one by(12.3%), the temperature distribution for the inner wall surface for the corrugated passage islower than circular one by (4.88 %). The coolant air flow velocity seems to be accelerated anddecelerated through the corrugated passage, so it was shown that the thermal performance factoralong the corrugated passage is larger than 1, this is due to the fact that the corrugated wallscreate turbulent conditions and increasing thermal surface area, and thus increasing heat transfercoefficient than the circular case.

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 Three-Dimensional CFD Modelling and Analysis of the Thermal Entrainment in Open Refrigerated Display Cabinets

2008 ◽  
Author(s):  
Pedro Dinis Gaspar ◽  
L. C. Carrilho Gonc¸alves ◽  
R. A. Pitarma
Keyword(s):  
Air Temperature ◽  
Mass Flow ◽  
Air Flow ◽  
Three Dimensional ◽  
Food Products ◽  
Ambient Air ◽  
Air Velocity ◽  
Air Curtain ◽  
Numerical Predictions ◽  
Thermal Entrainment

This study presents a three-dimensional Computational Fluid Dynamics (CFD) simulation of the air flow pattern and the temperature distribution in a refrigerated display cabinet. The thermal entrainment is evaluated by the variations of the mass flow rate and thermal power along and across the air curtain considering the numerical predictions of abovementioned properties. The evaluation on the ambient air velocity for the three-dimensional (3D) effects in the pattern of this type of turbulent air flow is obtained. Additionally, it is verified that the longitudinal air flow oscillations and the length extremity effects have a considerable influence in the overall thermal performance of the equipment. The non uniform distribution of the air temperature and velocity throughout the re-circulated air curtain determine the temperature differences in the linear display space and inside the food products, affecting the refrigeration power of display cabinets. The numerical predictions have been validated by comparison with experimental tests performed in accordance with the climatic class n.° 3 of EN 441 Standard (Tamb = 25 °C, φamb = 60%; νamb = 0,2 m s−1). These tests were conducted using the point measuring technique for the air temperature, air relative humidity and air velocity throughout the air curtain, the display area of conservation of food products and nearby the inlets/outlets of the air mass flow.

Combustion of Bio-Coke (Highly Densified Biomass Fuel) Block in High-Temperature Air Flow

2011 ◽  
Author(s):  
Hiroyuki Ito ◽  
Yuto Sakai ◽  
Tamio Ida ◽  
Yuji Nakamura ◽  
Osamu Fujita
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Mass Loss ◽  
Air Temperature ◽  
Degradation Rate ◽  
Loss Rate ◽  
Ignition Delay Time ◽  
Mass Loss Rate ◽  
Air Flow ◽  
Air Flow Rate

Bio-coke (BIC, highly densified biomass briquette), a newly developed biomass fuel as an alternative to coal coke which utilized in blast furnace, is employed in this study. This fuel is manufactured in highly compressed and moderate temperature conditions and has advantages in its versatility of biomass resources, high volumetric calorific value and high mechanical strength. Japanese knotweed is chosen as a biomass resource and is shaped into cylinder (48 mm in diameter and 85 mm in length). One of the most important characteristics of BIC is its high apparent density (1300 kg/m3; twice or more than that of an ordinary wood pellet). In the present study, combustion characteristics of a single BIC fuel in high temperature air flow (473–873 K, 550–750 NL/min.) are investigated. Air is preheated and blown to the bottom surface of the BIC. Ignition and subsequent combustion behavior are observed with monitoring gas temperature near the BIC, surface and inside the BIC temperature, and time dependent mass loss of the BIC is measured. In the case with low air temperature, low heat flux from the fuel surface leads to the broad temperature distribution inside the BIC accompanied by the increase in ignition delay time and, then, once ignition takes place degradation rate becomes larger than the case with high temperature air. On the other hand, mass loss rate for the case of solid surface combustion in the high temperature air does not depend on the air temperature but does depend on the air flow rate, which is a result of reduced degradation rate relating to narrow temperature distribution in depth caused by short ignition delay time. Consequently, it is suggested that the history of preheating, i.e. the preheated condition which is determined by air temperature and air flow rate, is an essential factor to determine the ignition mode in the early stage of BIC combustion and the mass burning velocity in the period of main combustion with flame. It is found that the mass loss rate of BIC in the gas-phase combustion period increases with decrease in supplied air temperature in this study.

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.

scholarly journals HVAC CFD Analysis of Air Flow and Temperature Distribution Inside Passenger Compartment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhamad Haziq Mohammad Aris ◽  
◽  
Nofrizalidris Darlis ◽  
Izuan Amin Ishak ◽  
Syabillah Sulaiman ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Air Temperature ◽  
Thermal Environment ◽  
Air Flow ◽  
Spatial And Temporal Variation ◽  
State Variables ◽  
Clothing Insulation ◽  
Vehicle Cabin ◽  
Air Blower ◽  
Good Agreement

The thermal environment and air quality in a passenger car can affect driver's and passengers' health, performance and comfort. Due to spatial and temporal variation of state variables and boundary conditions in the vehicle cabin, the heating, ventilating and air-conditioning (HVAC) does not have to be designed to provide a uniform environment. This are due to individual differences regarding to physiological and psychological response, clothing insulation, activity, air temperature and air movement preference. Experimental study in vehicle HVAC system can be very costly to be conducted. In order to analyze the air flow and temperature distribution in passengers compartment, a numerical simulation was used in this study to analyze the air flow and temperature distribution of HVAC unit inside Proton Exora passengers compartment, with the air blower speed and air temperature used as parameter, to evaluate the airflow behavior and temperature distribution in the compartment. The simulation data obtained is then compared to the experimental data, showing good agreement between these two methods.

scholarly journals Temperature distribution of a test specimen with high-speed heat air-flow passing through

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2527-2538 ◽  
Author(s):  
Kai Xiong ◽  
Yunhua Li ◽  
Sujun Dong
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Test Specimen ◽  
High Speed ◽  
Air Flow ◽  
Prediction Method ◽  
Average Temperature ◽  
Hot Air ◽  
Heat Transfer Theory ◽  
Good Agreement

In this paper, a solution method for the temperature distribution of rectangular test specimen with a high-speed heat air-flow passing through is proposed based on the heat transfer theory and numerical calculation, and the feasibility of temperature prediction method is validated. Firstly, the partial differential equations to describe the average temperature in the section of the hot air-flow and the specimen are established and the solving method using MATLAB solver is proposed. Then, based on heat transfer conduction equation and the average temperature, the temperature distribution at different point in each section is calculated. The comparison between numerical computation and experiment shows that two results are in good agreement, which verifies the correctness of the presented prediction method of the temperature distribution of the specimen.

Effect of microwave, infrared, and convection hot-air on drying kinetics and quality properties of okra pods

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hany S. EL-Mesery ◽  
Mona A. Elabd
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Drying Methods ◽  
Air Velocity ◽  
Rehydration Ratio ◽  
Drying Time ◽  
Shrinkage Ratio ◽  
Hot Air

Abstract Okra pods were dried using the following drying regimes; microwave (MWD), infrared (IRD) and convective hot-air drying (CHD). The objective of this investigate was to report the influences of drying methods on okra quality under different drying conditions. Data analysis showed that rehydration ratio and colour change increased with increase in drying air temperature and air velocity while specific energy consumption and shrinkage ratio decreased with increase in drying air temperature under (CHD). The rehydration ratio and colour of dried okra increased with increase in both infrared intensity but it also increased with a decrease in air velocity under (IRD). In the MWD method, drying time, specific energy consumption and shrinkage ratio decreased with increases in microwave power while the rehydration ratio and colour increased. Optimum drying period, specific energy consumption, colour, shrinkage and rehydration ratio were obtained for microwave drying. The model of Midilli et al. is the greatest for describing the drying curves of okra under all the drying processing conditions.

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