Experimental Modeling of Air Temperature and Velocity Distribution in an Engine Compartment

2006 ◽  
Author(s):  
A. A. Mozafari ◽  
M. H. Saidi ◽  
J. Neyestani ◽  
A. E. Sany
Keyword(s):  
Heat Transfer ◽  
Velocity Distribution ◽  
Air Temperature ◽  
Gasoline Engine ◽  
Point Of View ◽  
Vehicle Body ◽  
Air Distribution ◽  
Wind Effect ◽  
Engine Compartment ◽  
Air Velocity

Investigation of air distribution and wind effect on a vehicle body from the point of view of underhood heat transfer effect and proper positioning of vehicle elements such cooler, condenser and engine configuration is an important area for engine researchers and manufacturers as well. In this research, the effect of air velocity distribution and wind effect around a vehicle is simulated and temperature and velocity distribution around engine block which is influenced by the wind effect is investigated. Thermal investigation of the engine compartment components is performed using results of underhood air temperature and velocity distribution. The heat transfer from engine surface is calculated from the engine energy balance in which their input data are obtained from a comprehensive experimental study on a four cylinder gasoline engine.

Experimental Investigation on Heat Transfer Performance in an Underground Dam Tunnel of Hydropower Station

2011 ◽  
Vol 374-377 ◽  
pp. 494-497
Author(s):  
Yi Rong Dang ◽  
An Gui Li ◽  
Hai Guo Yin
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Air Temperature ◽  
Heat Transfer Performance ◽  
Transfer Characteristic ◽  
Hydropower Station ◽  
Transfer Performance ◽  
Air Velocity ◽  
Underground Dam ◽  
Ventilation Method

This paper presents an energy efficient ventilation method—dam tunnel air handling for hydropower station ventilation. The heat transfer characteristic between supply air and the dam tunnel is studied by model experiment. Supply air velocity, air temperature and dam tunnel surface roughness are chosen as the mainly influencing factors, the air temperature distribution along airflow direction are measured and analyzed in detail. The results show that the heat transfer performance in dam tunnel is improved as the increased of supply air temperature and the dam tunnel surface roughness, or maintained the supply air velocity at a lower level. This experimental study and its results are helpful to develop alternative and efficient systems for hydropower station ventilation.

Simplified Procedure for Prediction of Asphalt Pavement Subsurface Temperatures Based on Heat Transfer Theories

1997 ◽  
Vol 1568 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Lisheng Shao ◽  
Sun Woo Park ◽  
Y. Richard Kim
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Air Temperature ◽  
Asphalt Pavement ◽  
Prediction Method ◽  
Point Of View ◽  
Temperature History ◽  
Climatic Regions ◽  
Simplified Procedure ◽  
Subsurface Temperatures

Surface deflection measurements and backcalculation of layer moduli in flexible pavements are significantly affected by the temperature of the asphalt concrete (AC) layer. Correction of deflections or backcalculated moduli to a reference temperature requires determination of an effective temperature of the AC layer. For routine deflection testing and analysis in state highway agencies, it is preferable, from a practical point of view, to use a nondestructive prediction method for determining the effective AC layer temperature instead of measuring the temperature directly from a small hole drilled into the AC layer. A simplified procedure to predict asphalt pavement subsurface temperatures is presented. The procedure is based on fundamental principles of heat transfer and uses the surface temperature history since yesterday morning to predict the AC layer mid-depth temperature at the time of falling weight deflectometer (FWD) testing today. The surface temperature history is determined using yesterday’s maximum air temperature and cloud condition, the minimum air temperature of today’s morning, and surface temperatures measured during FWD tests. FWD tests and temperature measurements have been conducted on seven pavement sections with varying structural designs located in three different climatic regions of North Carolina. The field temperature records from these pavements have provided values of pavement thermal parameters and coefficients in temperature functions that are needed in the prediction procedure. A set of verification results are presented using examples with different climatic regions, changing AC layer thicknesses, and varying weather patterns in different seasons.

An Evaluation of the Wind Chill Factor: Its Development and Applicability

1998 ◽  
Vol 120 (2) ◽  
pp. 255-258 ◽  
Author(s):  
M. Bluestein
Keyword(s):  
Heat Transfer ◽  
Wind Velocity ◽  
Air Temperature ◽  
Wind Effect ◽  
Transfer Coefficients ◽  
Wind Chill ◽  
Heat Transfer Coefficients ◽  
Economic Significance ◽  
Two Factors ◽  
Transfer Principles

The wind chill factor has become a standard meteorologic term in cold climates. Meteorologic charts provide wind chill temperatures meant to represent the hypothetical air temperature that would, under conditions of no wind, effect the same heat loss from unclothed human skin as does the actual combination of air temperature and wind velocity. As this wind chill factor has social and economic significance, an investigation was conducted on the development of this factor and its applicability based on modern heat transfer principles. The currently used wind chill factor was found to be based on a primitive study conducted by the U.S. Antarctic Service over 50 years ago. The resultant equation for the wind chill temperature assumes an unrealistic constant skin temperature and utilizes heat transfer coefficients that differ markedly from those obtained from equations of modern convective heat transfer methods. The combined effect of these two factors is to overestimate the effect of a given wind velocity and to predict a wind chill temperature that is too low.

Effects of Human Gait on Air Distribution in Contagious Isolation Tent Wards

2013 ◽  
Vol 380-384 ◽  
pp. 1770-1773
Author(s):  
Gao Feng Wei ◽  
Zhan Shu ◽  
Gang Tang
Keyword(s):  
Air Pollution ◽  
Air Temperature ◽  
Pollution Control ◽  
Three Dimensions ◽  
Human Gait ◽  
Air Distribution ◽  
Air Pollution Control ◽  
Air Velocity ◽  
The Impact ◽  
Contaminant Distribution

The purpose of this study was to investigate the effects of human gait on air distribution in contagious isolation tent wards. The proposed contagious isolate tent wards were designed as the operating room for serious paroxysmal infectious patients. The three dimensions model of contagious isolation tent ward was reconstructed. Then, the computed fluid dynamical (CFD) methods were used to simulate and analyze the air distribution of contagious isolation tent ward. The dynamical meshes technology was employed to simulate the human gait. An experiment was implemented to measure air velocity of the proposed isolate tent ward. The results showed that the human gait motion affects air pressure, air velocity and contaminant distribution, while the impact on air temperature could be ignored. It was concluded that the impact of human gait or movements should be taken into account in air pollution control of contagious isolation tent wards.

CFD-Based Parametric Analysis on the Performance of Personalized Partition Air Distribution Systems

Solar Energy ◽  
2006 ◽  
Author(s):  
Kybum Jeong ◽  
Moncef Krarti ◽  
Zhiqiang Zhai
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Distribution System ◽  
Distribution Systems ◽  
Comfort Level ◽  
Cfd Modeling ◽  
Air Distribution ◽  
Air Velocity ◽  
Comfort Index ◽  
System Mode

The partition air distribution systems evaluated in this study allow occupants to control the system mode (on/off) and the supply air velocity and direction with similar flexibility as occupants in automobiles. To find optimal specifications for the partition air distribution systems that are able to achieve comfortable micro-environment, a CFD modeling tool was used to simulate the airflow and thermal performance of the partition air distribution systems in a typical office space. By analyzing the distribution characteristics of indoor air temperature, air velocity and thermal comfort index, the study assessed the performance of the partition air distribution systems with different operating parameters. The simulation results were analyzed and evaluated to assess both occupant’s thermal comfort and system energy consumption. The study shows that space cooling energy can be reduced while maintaining acceptable indoor thermal comfort level using a partition air distribution system with a higher supply air temperature.

Heat and Mass Transfer Characteristics of a Finned-Tube Evaporator Under Frosting Conditions

2001 ◽  
Author(s):  
Y. H. Kim ◽  
Y. J. Park ◽  
Y. C. Kim ◽  
S. C. Shim ◽  
S. K. Oh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Air Temperature ◽  
Early Stage ◽  
Finned Tube ◽  
Airflow Rate ◽  
Air Velocity ◽  
Frost Formation ◽  
Transfer Characteristics

Abstract An experimental study was performed to investigate the heat and mass transfer characteristics of a finned-tube evaporator coil utilized in a domestic refrigerator under frosting conditions. Airside heat transfer coefficient was measured as a function of air temperature, humidity ratio, air velocity, and evaporating temperature. In addition, frost thickness was monitored and measured by visualization tests during frosting operation. Based on the experimental results, the degradation of heat transfer performance due to frost formation was explored as a function of operating parameters. The rate of frost formation on the evaporator increases at relatively high humidity, high airflow rate, low inlet air temperature and low refrigerant temperature. As the frost thickness increases, airflow rate gradually decreases, while the capacity increases at the early stage of frost formation and then significantly drops.

Indoor air distribution in a room with underfloor air distribution and chilled ceiling: Effect of ceiling surface temperature and supply air velocity

2019 ◽  
Vol 29 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Jie Gao ◽  
Haichao Wang ◽  
Xiaozhou Wu ◽  
Fenghao Wang ◽  
Zhen Tian
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Indoor Air ◽  
Residential Buildings ◽  
Air Distribution ◽  
Cooling Load ◽  
Air Velocity ◽  
Underfloor Air Distribution ◽  
Chilled Ceiling ◽  
Cooling Loads

An underfloor air distribution (UFAD) system integrated with a chilled ceiling (CC) cooling system may be a potential advanced heating, ventilation and air conditioning system in modern non-residential buildings with high sensible cooling loads. This article presents an experimental study concerning the effect of ceiling surface temperature and supply air velocity on the indoor air distribution in a room with UFAD as the internal and external sensible cooling loads change. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by vertical air temperature difference (VATD), turbulence intensity (TI) and contaminant removal effectiveness (CRE), respectively. The results showed that the average VATD, TI and CRE levels were 0.5°C–1.0°C, 31%–41% and 0.85–1.06 when both internal and external sensible cooling loads were 41.5 W/m2. These evaluation indices varied clearly when the external sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2, whereas they remained almost the same when the internal sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2. The maximum TI coincided with the minimum CRE under the condition of a constant sensible cooling load. Moreover, an air diffusion performance index clearly reduced with an increase in the heat removal effectiveness. It is recommended that it is important to balance the indoor air quality and energy consumption in a room with UFAD + CC.

scholarly journals Agglomeration process in the fluidized bed, the effecting parameters and some applications

2018 ◽  
Vol 13 (3-4) ◽  
pp. 159-163
Author(s):  
Hira Yuksel ◽  
Nur Dirim
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Air Temperature ◽  
Mechanical Resistance ◽  
High Porosity ◽  
Air Velocity ◽  
Mixing Rate ◽  
Agglomeration Process ◽  
Mass And Heat Transfer ◽  
Bed Agglomeration

The agglomeration process has been commonly used to improve the functional properties of powder products to form larger agglomerates. Agglomeration provides a granular structure to powders, reduce the dusting and improving their characteristics, such as storage stability, wettability, dispersibility, and solubility. This process can be performed by different methods, one of which is fluidized bed agglomeration widely used in food processing since the agglomerates produced by this technique have high porosity, low density, and good mechanical resistance. At the same time, this process is influenced by many factors; e.g., inlet air temperature, air velocity, mixing rate, and properties of the binder agents. Inlet air temperature affects the mass and heat transfer; air velocity prevents caking and accelerates mass and heat transfer; mixing rate allows mixing the binder agent uniformly over the particles; and the properties of the binder agent, such as concentration and viscosity have an impact on the properties of the final product. These four factors should be well known and controlled so that the agglomerates produced have the desired properties. Furthermore, the use of fluidized bed agglomeration results in products that can be used in widespread areas and in high quantities, and this method also creates the opportunity to utilize excess foods not consumed.

Numerical Analysis on Heat Transfer Characteristics of Double Ventilation Glass with Hot Channel

2012 ◽  
Vol 512-515 ◽  
pp. 2887-2890
Author(s):  
Han Bing Qi ◽  
Yu Shi Wang ◽  
Qiu Shi Wang ◽  
Jing Wang ◽  
Dong Li
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Flow Rate ◽  
Structural Characteristics ◽  
Air Distribution ◽  
Transfer Model ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up

The structural characteristics and heat transfer characteristics of double ventilation glass with hot channel are analyzed, whose heat transfer model is set up, we simulate air distribution of double ventilation glass with hot channel using Computational Fluid Dynamics (CFD) scheme as a simulation technique. The results show that the requirement of supplying air can be realized in winter, when the heating plates are set up in the hot channel, the air temperature of outlet is 290 K, and the flow rate of outlet is 1.03 m/s; which can be realized in summer, when the cooling plates are set up in the hot channel, the air temperature of outlet is 290 K, and the flow rate of outlet is 1.12m/s.

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