scholarly journals The Optimum Thickness of Rockwool as Roof Thermal Insulation: An Experimental and Numerical Study

2021 ◽  
Vol 89 (1) ◽  
pp. 77-91
Author(s):  
Mohammed W. Muhieldeen ◽  
Lim Chong Lye ◽  
Mohammed Sameer Sharaf Kassim ◽  
Wah Yen Tey ◽  
Kah Hou Teng
Keyword(s):  
Numerical Study ◽  
Experimental Result ◽  
Cfd Analysis ◽  
Optimum Thickness ◽  
Air Velocity ◽  
Infrared Thermometer ◽  
Electricity Bill ◽  
Lecture Room ◽  
Heating Load ◽  
Rock Wool

Now a days, the global warming has increased the temperature in the environment that forced the building occupant to get assisting from the air condition to reduce the heat tension inside the building, this could increase the electricity bill amount. The aim of this study is to measure the optimum thickness of Rockwool insulation to experimentally and numerically to reduce the heating load inside the buildings. Two devices have been used through this research, Infrared Thermometer to measure profile temperature of the walls along with VELOCICALC to measure the air temperature and air velocity. Three different layers of Rockwool insulation have been applied on the roof of wooden room. The data present the two layers thickness of Rockwool is the best selection to reduce the heating load inside the room, the differential between outside and inside is 0.9 °C, the Rockwool of one layer reduced only 0.5 °C and the maximum thickness with three layers reduced only 1 °C, which is not much effective compared to the two layers but even more costly. CFD analysis shows agreement with the experimental result. The results shows if the dimensions of a UCSI lecture room is to be considered, then applying Rockwool insulation with a thickness of 100 mm would cost around RM 1520 as a UCSI lecture room is of 8 m width and 9 m length. However, two layers of Rock wool insulation could save around 29.30% of ROI per annum.

scholarly journals Contribution to the Sustainability of Agricultural Production in Greenhouses Built on Slope Soils: A Numerical Study of the Microclimatic Behavior of a Typical Colombian Structure

2021 ◽  
Vol 13 (9) ◽  
pp. 4748
Author(s):  
Edwin Villagran ◽  
Carlos Bojacá ◽  
Mohammad Akrami
Keyword(s):  
Latin American ◽  
Crop Yields ◽  
Numerical Study ◽  
Air Flow ◽  
Research Work ◽  
Flow Patterns ◽  
Soil Conditions ◽  
Air Velocity ◽  
The Hours ◽  
Microclimatic Conditions

The use of covered structures is an alternative increasingly used by farmers to increase crop yields per unit area compared to open field production. In Latin American countries such as Colombia, productive areas are located in with predominantly hillside soil conditions. In the last two decades, farmers have introduced cover structures adapted to these soil conditions, structures for which the behavior of factors that directly affect plant growth and development, such as microclimate, are still unknown. Therefore, in this research work, a CFD-3D model successfully validated with experimental data of temperature and air velocity was implemented. The numerical model was used to determine the behavior of air flow patterns and temperature distribution inside a Colombian passive greenhouse during daytime hours. The results showed that the slope of the terrain affects the behavior of the air flow patterns, generating thermal gradients inside the greenhouse with values between 1.26 and 16.93 °C for the hours evaluated. It was also found that the highest indoor temperature values at the same time were located in the highest region of the terrain. Based on the results of this study, future researches on how to optimize the microclimatic conditions of this type of sustainable productive system can be carried out.

Experimental and numerical study of an overlay composite absorber plate material for a solar air heater

2021 ◽  
Vol 63 (7) ◽  
pp. 681-686
Author(s):  
Duraisamy Jagadeesh ◽  
Ramasamy Venkatachalam ◽  
Gurusamy Nallakumarasamy
Keyword(s):  
Numerical Study ◽  
The Other ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Cfd Analysis ◽  
Plate Material ◽  
Absorber Plate ◽  
Air Heater ◽  
Margin Of Error ◽  
Computational Processes

Abstract The research in this paper is a sequel of an earlier work by the author in which experimental and CFD results were compared for an absorber plate made of iron with and without fins for two flow rates. The research yielded a good comparative result between the experimental and computational process for an optimized flow rate and the effect of the fins. The objective of this paper is to verify the effect of the overlay composite absorber plate material on a solar air heater through experimental and computational fluid dynamics. The experimental setup consists of an absorber plate as an overlay composite of aluminum and copper for enhanced heat transfer. Experiments and CFD analysis were done in three configurations. In configuration one, only the aluminum absorber plate with fins was considered. In configuration two, the overlay composite was considered with copper on the top and aluminum at the bottom as fins, and in configuration three, the overlay composite was considered with aluminum at the top and copper at the bottom as fins. A transient 8 hours CFD analysis was carried out using these configurations. While validating the results it was found that the overlay absorber plate Cu-Al was capable of generating a high outlet temperature Max of 88 °C and capable of generating 83 °C air for 5 hours and had good thermal efficiency when compared to the other materials in the other two configuration. It was found that experimental and computational analysis were in very close agreement, and the margin of error between the experimental and computational processes was less than 8 %.

Validation of Film Evaporation Model in GASFLOW-MPI

2018 ◽  
Author(s):  
Li Yabing ◽  
Zhang Han ◽  
Xiao Jianjun
Keyword(s):  
Experimental Data ◽  
Wall Temperature ◽  
Cooling System ◽  
Numerical Study ◽  
Thermal Power ◽  
Heat Removal ◽  
Air Velocity ◽  
Evaporation Model ◽  
Film Evaporation ◽  
Test Region

A dynamic film model is developed in the parallel CFD code GASFLOW-MPI for passive containment cooling system (PCCS) utilized in nuclear power plant like AP1000 and CAP1400. GASFLOW-MPI is a widely validated parallel CDF code and has been applied to containment thermal hydraulics safety analysis for different types of reactors. The essential issue for PCCS is the heat removal capability. Research shows that film evaporation contributes most to the heat removal capability for PCCS. In this study, the film evaporation model is validated with separate effect test conducted on the EFFE facility by Pisa University. The test region is a rectangle gap with 0.1m width, 2m length, and 0.6m depth. The water film flowing from the top of the gap is heated by a heating plate with constant temperature and cooled by countercurrent air flow at the same time. The test region model is built and analyzed, through which the total thermal power and evaporation rate are obtained to compare with experimental data. Numerical result shows good agreement with the experimental data. Besides, the influence of air velocity, wall temperature and gap widths are discussed in our study. Result shows that, the film evaporation has a positive correlation with air velocity, wall temperature and gap width. This study can be fundamental for our further numerical study on PCCS.

Numerical Study on Supersonic Combustor with an Allotype Cavity

2014 ◽  
Vol 694 ◽  
pp. 187-192
Author(s):  
Jin Xiang Wu ◽  
Jian Sun ◽  
Xiang Gou ◽  
Lian Sheng Liu
Keyword(s):  
Alternative Model ◽  
Numerical Study ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Experimental Result ◽  
Navier Stokes ◽  
Cold Flow ◽  
Hypersonic Inlet ◽  
Good Agreement

The three-dimensional coupled explicit Reynolds Averaged Navier–Stokes (RANS) equations and the two equation shear-stress transport k-w (SST k-w) model has been employed to numerically simulate the cold flow field in a special-shaped cavity-based supersonic combustor. In a cross-section shaped rectangular, hypersonic inlet with airflow at Mach 2.0 chamber, shock structures and flow characteristics of a herringbone-shaped boss and a herringbone-shaped cavity models were discussed, respectively. The results indicate: Firstly, according to the similarities of bevel-cutting shock characteristics between the boss case and the cavity case, the boss structure can serve as an ideal alternative model for shear-layer. Secondly, the eddies within cavity are composed of herringbone-spanwise vortexes, columnar vortices in the front and main-spanwise vortexes in the rear, featuring tilting, twisting and stretching. Thirdly, the simulated bottom-flow of cavity is in good agreement with experimental result, while the reverse flow-entrainment resulting from herringbone geometry and pressure gradient. However, the herringbone-shaped cavity has a better performance in fuel-mixing.

Numerical analysis of supersonic co-flow jet with varying lip thickness

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sathish Kumar K ◽  
Naren Shankar R ◽  
Anusindhiya K ◽  
Senthil Kumar B.R
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Supersonic Nozzle ◽  
Experimental Result ◽  
Content Type ◽  
Jet Mixing ◽  
Mixing Characteristics ◽  
Jet Axis

Purpose This study aims to present the numerical study on supersonic jet mixing characteristics of the co-flow jet by varying lip thickness (LT). The LT chosen for the study is 2 mm, 7.75 mm and 15 mm. Design/methodology/approach The primary nozzle is designed for delivering Mach 2.0 jet, whereas the secondary nozzle is designed for delivering Mach 1.6 jet. The Nozzle pressure ratio chosen for the study is 3 and 5. To study the mixing characteristics of the co-flow jet, total pressure and Mach number measurements were taken along and normal to the jet axis. To validate the numerical results, the numerical total pressure values were also compared with the experimental result and it is proven to have a good agreement. Findings The results exhibit that, the 2 mm lip is shear dominant. The 7.75 mm and 15 mm lip is wake dominant. The jet interaction along the jet axis was also studied using the contours of total pressure, Mach number, turbulent kinetic energy and density gradient. The radial Mach number contours at the various axial location of the jet was also studied. Practical implications The effect of varying LT in exhaust nozzle plays a vital role in supersonic turbofan aircraft. Originality/value Supersonic co-flowing jet mixing effectiveness by varying the LT between the primary supersonic nozzle and the secondary supersonic nozzle has not been analyzed in the past.

scholarly journals Numerical Study on Humidification Performance of Fuel Cell Test Platform Humidifier

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3839 ◽  
Author(s):  
Tiancai Ma ◽  
Kai Wang ◽  
Qiongqiong Zhou ◽  
Weikang Lin ◽  
Ming Cong ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Water Temperature ◽  
Numerical Study ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Air Velocity ◽  
Humidity Control ◽  
Test Platform ◽  
Temperature And Humidity ◽  
Cell Test

Temperature and humidity are important parameters in the operation of proton exchange membrane fuel cell (PEMFC), which have an important impact on the performance of fuel cell. Fuel cell test platform is an important tool to study the performance of fuel cells, and its temperature and humidity control module is also the key in the research process of the test platform, so that it can provide the gas with precise temperature and humidity control during the test process of the fuel cell. In this paper, a humidifier combined with bubbling and spraying is adopted for the application of test platform, and the numerical simulation model of the humidifier is established. According to the model, the influence of operating conditions of humidifier on humidification performance is verified, such as inlet air velocity and the humidifying water temperature. The results indicate that the inlet air velocity and the humidifying water temperature have great influence on the humidifying performance of the humidifier. The humidifying performance decreases with the increase of the inlet air velocity and increases with the increase of the humidifying water temperature respectively. In addition, the humidification performance of the humidifier is verified.

Numerical Study on Structure Thermal Protection of Aerospace Plane

2014 ◽  
Vol 900 ◽  
pp. 814-817
Author(s):  
Shuang Chen ◽  
Qing Feng Zhang
Keyword(s):  
Thermal Protection ◽  
Numerical Study ◽  
Thermal Protection System ◽  
Protection System ◽  
Flow Density ◽  
Air Velocity ◽  
The Status ◽  
Flight Parameters ◽  
Cooling Air ◽  
Aerospace Plane

The letter relying on the status of existing thermal protection system and existing flight parameters, appropriate metal thermal protection system being able to reproduced are designed; according to the distribution of heat-flow density we make certain the structure and thickness of the heat shield, structure of cooling bed and pressure of cooling air, velocity of flow and so on. The distributions of temperature of points on the nose and the inside of skin are calculated.

Numerical Study of the Efficiency of Flat Plate Solar Collectors in Different External Conditions

2014 ◽  
Vol 659 ◽  
pp. 435-439
Author(s):  
Cătălin George Popovici ◽  
Sebastian Hudisteanu
Keyword(s):  
Solar Radiation ◽  
Flat Plate ◽  
Numerical Study ◽  
Solar Thermal ◽  
Solar Panels ◽  
Air Velocity ◽  
External Temperature ◽  
Renewable Source ◽  
Inlet Flow Rate ◽  
External Conditions

In this paper is presented a numerical investigation of efficiency of the solar thermal panels for different external conditions. The aim of the study was the analysis of flat plate solar panels that are placed in a temperate zone, such as the climate of Romania. The opportunity of the study is proven by the growing tendency in using renewable source of energy and especially of the solar thermal one. The variables considered in the study were the inlet flow rate, external temperature, air velocity and intensity of solar radiation.

Numerical Study on Effect of Covered Water in Thawing Frozen Soil by Explosive Load

2013 ◽  
Vol 767 ◽  
pp. 211-216
Author(s):  
Hideki Hamashima ◽  
Toshiaki Watanabe ◽  
Hironori Maehara ◽  
Kazuyuki Hokamoto ◽  
Shigeru Itoh
Keyword(s):  
Numerical Simulation ◽  
Numerical Study ◽  
Frozen Soil ◽  
Experimental Result ◽  
Cold Region ◽  
Explosive Load ◽  
Simple Experiment

It is known to be able to expect the improvement of the harvest if the cropping time can be made early in a cold region such as Russia, Norway, Sweden and Hokkaido in Japan. Therefore, for the purpose of making cropping time early as much as possible, we researched the destruction of the frozen soil by the explosive. In the simple experiment, as compared with the experiment which placed the explosive directly on top of the frozen soil, it broke greatly in the experiment which poured out water 20 mm in height after placing an explosive directly on top of the frozen soil. Furthermore, it was found that the thawing time of residual frozen soil in the experiment using water is shorter than without water. In this research, in order to investigate the effect of the covered water in thawing frozen soil by explosive load, the numerical simulation was performed. The result of the numerical simulation was well in agreement with the experimental result, and it was clarified that destruction effect is increased by covering with water.

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