Meramal Aliran Udara dan Keselesaan di dalam Masjid Sultan Salahuddin Abdul Aziz Shah Menggunakan Simulasi Komputer

2014 ◽  
Vol 69 (1) ◽  
Author(s):  
Shamsul Sarip ◽  
Mat Nawi Wan Hassan
Keyword(s):  
Temperature Distribution ◽  
Flow Direction ◽  
Ventilation System ◽  
Computer Software ◽  
Comfort Level ◽  
Two Dimensional ◽  
Air Velocity ◽  
Temperature Distributions ◽  
Air Supply ◽  
Consumer Dissatisfaction

A study on ventilation system using a two dimensional turbulence k-e model with the assumption that the fluid is incompressible and non-isothermal is presented. The purpose of this study is to predict the distribution of air velocity and temperature in main hall Masjid Sultan Salahuddin Abdul Aziz Shah in Shah Alam.  When the airflow and temperature distribution have been predicted by the computer software FLUENT, the comfort level can easily be determined. Nine cases have been conducted to examine the effects of input air velocity, air velocity from the fan heli and fan air flow direction to the percentage of consumer dissatisfaction. Mixing characteristics of comfort have been analyzed under different air supply velocities, temperatures and fan velocities. The fan velocity directions involved two conditions which are the upwards and downwards directions. The results from the research in the form of air velocity and temperature distributions are important in determining the comfort level which is unsuitable for the user. It was found that cases of 3,4, 5, 6 and 7 show the effect of a very good comfort with the percentage of PPD between 10% to 20%. The location of heli fans also affects the impression of comfort in the main hall. The comfort level of this area can be improved by modifying the position and increasing the number of fans in the hall.

scholarly journals Air flow characteristics of a room with air vortex diffuser

2018 ◽  
Vol 240 ◽  
pp. 02002 ◽  
Author(s):  
Marek Borowski ◽  
Marek Jaszczur ◽  
Daniel Satoła ◽  
Michał Karch
Keyword(s):  
Air Flow ◽  
Ventilation System ◽  
Flow Characteristics ◽  
Comfort Level ◽  
Translational Velocity ◽  
Comfort Zone ◽  
Air Velocity ◽  
Velocity Decay ◽  
Different Diameters ◽  
Comfort Criteria

The air diffuser is a very important component of any ventilation system, and the comfort level of ventilated space occupants depend among many other factors on properly designed and choice of diffusers. At present a large number of diffusers are produced to meet a different kind of requirements. One of the most efficient and very popular types of the diffuser is the vortex diffuser in which air flow has angular as well as translational velocity components. This paper investigates experimentally airflow characteristics of vortex ceiling diffuser and its effect on airflow in a ventilated space. Two thermal comfort criteria namely: mean age of the air and ventilation effectiveness have been used to predict the comfort zone inside the room. Effect of supply air velocity on the flow field is investigated and hence the on comfort and energy consumption. The results show that significant amount of energy can be saved by using vortex diffuser in reference to the other diffusers type. The values of the velocity decay coefficient were compared for different diameters of vortex diffuser.

scholarly journals Enhancement of Airborne Particles Removal in a Hospital Operating Room

2019 ◽  
Vol 16 (4) ◽  
pp. 7447-7463
Author(s):  
K. Y. Wong ◽  
H. M. Kamar ◽  
N. Kamsah
Keyword(s):  
Operating Room ◽  
Numerical Study ◽  
Ventilation System ◽  
Airborne Particles ◽  
Operating Table ◽  
Particle Removal ◽  
Discrete Phase Model ◽  
Air Velocity ◽  
Air Supply ◽  
Discrete Phase

This article presents the results of a numerical study to examine the transport of particles in an operating room equipped with an Econoclean ventilation system. Its aims are to reduce the number of particles falling onto the operating table. A simplified CFD model of the operating room was developed and validated based on the measured air velocity distribution. An SST k-ω turbulent flow model was used to simulate the airflow, while a discrete phase model was used to simulate the movement of the airborne particles. The effects of the standing posture of the surgical staff on the settlement of the particles on the operating table were examined. Results show that under the present ventilation system, when the surgical staff bend forward at an angle of 45°,  the number of airborne particles that tend to fall onto the operating table increased by 1.4-fold. Adding an exhaust grille to the operating room does not have any significant effects on the distribution of the airborne particles. However, when a larger air supply diffuser is also used, the number of airborne particles that settled on the operating table was reduced 4-fold. More airborne particles are transported towards the exhaust grilles, and more airborne particles accumulate below the operating table. The present study shows that the usage of large air supply diffuser in the operating room is capable of reducing the number of airborne particles fall onto the operating table. Also, it enhances the efficiency of airborne particle removal.

scholarly journals Enhancement of Thermal Comfort Inside the Kitchen of Non-Airconditioned Railway Pantry Car

2021 ◽  
Vol 39 (1) ◽  
pp. 275-291
Author(s):  
Md Sarfaraz Alam ◽  
Urmi Ravindra Salve
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Ventilation System ◽  
Comfort Level ◽  
Air Velocity ◽  
Sustainable Improvement ◽  
Study Results ◽  
Air Ventilation

There are ample literature studies available, focusing on hot-humid built environment, which have achieved an increase in thermal comfort conditions by proper installation of ventilation-systems. The present thermal comfort study has been carried out in the kitchen environment of a non-air-conditioned railway pantry car in Indian Railways. The purpose is to enhance thermal comfort level under the currently applied ventilation system inside the kitchen of pantry car by determining the standard effective temperature (SET) index. During the summer and winter seasons, a field study was carried out to obtain the value of air temperature, globe temperature, relative humidity, and air velocity inside the pantry car for estimation of the SET index. A computational fluid dynamics (CFD) analysis was used to obtain a better-modified case model of the pantry car kitchen for the improvement of thermal comfort. The design interventions for the pantry car kitchen were created, with emphasis on increasing energy efficiency based on low-power consumption air ventilation system. The study results indicated that, modified case-I model has a better ventilation design concept as compare to the existing and other models, which increased the air velocity and significantly decreased the air temperature inside the kitchen of pantry car at all cooking periods. A value of SET (28.6–30℃) was found with a comfortable thermal sensation within all cooking periods, which is better for the pantry car workers. This finding suggests a sustainable improvement in the thermal environment of the "non-air-conditioned" pantry car kitchen in the Indian Railways, which can be applied immediately.

Effect of nozzle air supply temperature and volume flowrate on the jet flow from a typical ventilation nozzle in aircraft cabins

2016 ◽  
Vol 27 (4) ◽  
pp. 499-511 ◽  
Author(s):  
Xiuyuan Du ◽  
Baizhan Li ◽  
Hong Liu ◽  
Yuxin Wu ◽  
Tengfei Cheng ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Velocity Distribution ◽  
Thermal Comfort ◽  
Temperature Difference ◽  
Air Velocity ◽  
Aircraft Cabins ◽  
Aircraft Cabin ◽  
Air Supply ◽  
Published Research ◽  
Main Region

A ventilation nozzle’s airflow characteristics could have an influence on a passenger’s thermal comfort and dispersion of pollutants in an aircraft cabin, but there is little published research in this area. In this article, the temperature and air velocity from a nozzle jet were measured in a simulated three-row aircraft cabin at more than 220 points for both isothermal and non-isothermal jets. The non-isothermal jets were tested for air supply temperature differences of ± 5 and 10℃, and the isothermal jets for volume flowrates of 1.86 × 10−7, 2.67 × 10−7, and 4.03 × 10−7 m3/h. The results show that both the nozzle jet’s temperature and air velocity distributions are axially symmetrical and that the decay of the jet is rapid. The equation for the air velocity distribution was used to calculate the air velocity at any point in the main jet region for different volume flowrates. The temperature difference was shown to have little effect on the air velocity distribution for the main region of a nozzle jet, whereas the air flowrate was shown to significantly affect the air velocity distribution. This suggests that the effect of nozzle jet on passenger’s thermal comfort is mostly due to its air velocity distribution rather than temperature distribution.

scholarly journals Evaluating Life Cycle of Buildings Using an Integrated Approach Based on Quantitative-Qualitative and Simplified Best-Worst Methods (QQM-SBWM)

2021 ◽  
Vol 13 (8) ◽  
pp. 4487
Author(s):  
Maghsoud Amiri ◽  
Mohammad Hashemi-Tabatabaei ◽  
Mohammad Ghahremanloo ◽  
Mehdi Keshavarz-Ghorabaee ◽  
Edmundas Kazimieras Zavadskas ◽  
...  
Keyword(s):  
Life Cycle ◽  
Computer Software ◽  
Integrated Approach ◽  
Comfort Level ◽  
Combination Method ◽  
New Combination ◽  
Numerical Examples ◽  
Environmental Consequences ◽  
Time Required

Evaluating the life cycle of buildings is a valuable tool for assessing sustainability and analyzing environmental consequences throughout the construction operations of buildings. In this study, in order to determine the importance of building life cycle evaluation indicators, a new combination method was used based on a quantitative-qualitative method (QQM) and a simplified best-worst method (SBWM). The SBWM method was used because it simplifies BWM calculations and does not require solving complex mathematical models. Reducing the time required to perform calculations and eliminating the need for complicated computer software are among the advantages of the proposed method. The QQM method has also been used due to its ability to evaluate quantitative and qualitative criteria simultaneously. The feasibility and applicability of the SBWM were examined using three numerical examples and a case study, and the results were evaluated. The results of the case study showed that the criteria of the estimated cost, comfort level, and basic floor area were, in order, the most important criteria among the others. The results of the numerical examples and the case study showed that the proposed method had a lower total deviation (TD) compared to the basic BWM. Sensitivity analysis results also confirmed that the proposed approach has a high degree of robustness for ranking and weighting criteria.

Intelligent simulation experimental study on influence of air velocity of air supply hood and exhaust hood with vertical push-pull ventilation

2019 ◽  
Vol 37 (4) ◽  
pp. 4819-4826 ◽  
Author(s):  
Lindong Liu ◽  
Jingwen Dai ◽  
Junwei Yang ◽  
Miao Jin ◽  
Wei Jiang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Exhaust Hood ◽  
Air Velocity ◽  
Air Supply ◽  
Intelligent Simulation

An analytical solution of a two-dimensional temperature field in a hollow cylinder under a time periodic boundary condition using Fourier series

2009 ◽  
Vol 223 (8) ◽  
pp. 1889-1901 ◽  
Author(s):  
G Atefi ◽  
M A Abdous ◽  
A Ganjehkaviri ◽  
N Moalemi
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Fourier Series ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Hollow Cylinder ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Separation Of Variables ◽  
Two Dimensional

The objective of this article is to derive an analytical solution for a two-dimensional temperature field in a hollow cylinder, which is subjected to a periodic boundary condition at the outer surface, while the inner surface is insulated. The material is assumed to be homogeneous and isotropic with time-independent thermal properties. Because of the time-dependent term in the boundary condition, Duhamel's theorem is used to solve the problem for a periodic boundary condition. The periodic boundary condition is decomposed using the Fourier series. This condition is simulated with harmonic oscillation; however, there are some differences with the real situation. To solve this problem, first of all the boundary condition is assumed to be steady. By applying the method of separation of variables, the temperature distribution in a hollow cylinder can be obtained. Then, the boundary condition is assumed to be transient. In both these cases, the solutions are separately calculated. By using Duhamel's theorem, the temperature distribution field in a hollow cylinder is obtained. The final result is plotted with respect to the Biot and Fourier numbers. There is good agreement between the results of the proposed method and those reported by others for this geometry under a simple harmonic boundary condition.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

The Effect of Bench Arrangements on the Natural Ventilation of a Multispan Greenhouse

2013 ◽  
Author(s):  
Sunita Kruger ◽  
Leon Pretorius
Keyword(s):  
Fluid Dynamics ◽  
Natural Ventilation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Low Velocity ◽  
Lower Velocity ◽  
Cfd Models ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Cfd ◽  
Plant Level

In this paper, the influence of various bench arrangements on the microclimate inside a two-span greenhouse is numerically investigated using three-dimensional Computational Fluid Dynamics (CFD) models. Longitudinal and peninsular arrangements are investigated for both leeward and windward opened roof ventilators. The velocity and temperature distributions at plant level (1m) were of particular interest. The research in this paper is an extension of two-dimensional work conducted previously [1]. Results indicate that bench layouts inside the greenhouse have a significant effect on the microclimate at plant level. It was found that vent opening direction (leeward or windward) influences the velocity and temperature distributions at plant level noticeably. Results also indicated that in general, the leeward facing greenhouses containing either type of bench arrangement exhibit a lower velocity distribution at plant level compared to windward facing greenhouses. The latter type of greenhouses has regions with relatively high velocities at plant level which could cause some concern. The scalar plots indicate that more stagnant areas of low velocity appear for the leeward facing greenhouses. The windward facing greenhouses also display more heterogeneity at plant level as far as temperature is concerned.

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