Investigation of Airflow and Temperature Distribution in the Freezer Cabinet of a Domestic No-Frost Refrigerator

2009 ◽  
Author(s):  
Melike Nikbay ◽  
M. Berkay Acikgoz ◽  
Husnu Kerpicci
Keyword(s):  
Energy Consumption ◽  
Temperature Distribution ◽  
Uniform Temperature ◽  
Flow Conditions ◽  
Piv Measurements ◽  
Factors Affecting ◽  
Flow And Heat Transfer ◽  
Cfd Analyses ◽  
Off Time ◽  
Laminar Flow Conditions

Uniformity of temperature distribution in a loaded freezer cabinet is one of the most important factors affecting energy consumption of a refrigerator. Present study focuses on the airflow behavior and the temperature distribution inside the freezer compartment of a domestic no-frost refrigerator. Energy consumption increases in a freezer cabinet if the temperature difference between the warmest load package and average of all packages is high. The objective is to reduce the energy consumption by providing a uniform temperature distribution and also to keep the food fresh for a longer time. In this study, the air flow and heat transfer during on-time and off-time periods inside the freezer compartment is modeled by considering turbulent and laminar flow conditions in 3D transient CFD analyses. The initial and boundary conditions are provided from temperature controlled room and PIV measurements. The CFD analyses obtained are verified by experimental measurements.

Effect of Hot Bar Shape on Temperature Consistency

2008 ◽  
Vol 33-37 ◽  
pp. 1319-1326 ◽  
Author(s):  
Meng Ju Lin ◽  
Jen Cheh Lee ◽  
Chung Li Hwan ◽  
Jung Nan Liao
Keyword(s):  
Temperature Distribution ◽  
Heating Time ◽  
Heating Process ◽  
Uniform Temperature ◽  
Welding Temperature ◽  
Factors Affecting ◽  
Four Dimensions ◽  
Uniform Temperature Distribution ◽  
Circular Holes ◽  
Welding Properties

Pulse heated reflow soldering is widely used as junction methods of electronic devices such as ACF, HSC, FPC, PCB, TCP, and FFC. Hot bars are the devices used in pulsed heated reflow method to heat and melt the solder materials between devices and wire becoming a junction. Therefore the performance is determined by the welding properties. The welding time, temperature and induced pressure are important factors affecting welding property. And the temperature has the significant effect due to electricity and mechanical property of solder being determined by welding temperature. However, the consistency of temperature is hard to achieve due to complex coupling of driving current, materials property, heat generation, heat conduction and hot bar shape. In this work, different shapes of hot bat are designed to obtain the temperature consistency. Due to the welding requirement, the heating process is a two steps process. And the hot bar is heated by electric current from power supply with feedback control. For assembly purpose, the hot bar is designed as a rectangular plate with circular holes near the other side respect to the heating edge to fasten the hot bar on the welding machine. And the hot bar with polygon hole in the center part would induce the uniform temperature distribution. Four dimensions of the hot bar determine the shape and investigate the temperature consistency: polygon’s sizes and its positions. Some experiments are made to measure the temperature distribution. The results show the shape has significant effect on temperature consistency. Changing the polygon hole positions will alter the temperature distribution. The central part of heating edge will hotter than both ending part initially. And in some cases, during the heating process, the both ending part will have cooler, hotter, and cooler temperature that central part with respect to heating time. The polygon hole sizes have also significant effect on the temperature distribution. They have the similar temperature distribution phenomena as positions effect. Therefore, from the experiments and analysis, the hot bar could have more uniform temperature distribution by shape design. And it is also found the temperature distribution would induce thermal residual stress and deform the hot bar.

scholarly journals Theoretical Analysis of Unit Friction Force Working on the Metal Contact Surface with the Roll Change during Feedstock with Non-Uniform Temperature Distribution Rolling Process

2016 ◽  
Vol 61 (2) ◽  
pp. 927-932
Author(s):  
P. Sygut
Keyword(s):  
Temperature Distribution ◽  
Friction Force ◽  
Contact Surface ◽  
Rolling Process ◽  
Metal Contact ◽  
Uniform Temperature ◽  
Factors Affecting ◽  
Uniform Temperature Distribution ◽  
Engineering Data ◽  
Major Factors

Abstract The paper presents the results of theoretical studies influence of non-uniform temperature distribution along the feedstock length to the unit friction force working on the metal contact surface with the roll change during the round bars 70 mm in diameter continuous rolling process. This value is one of the major factors affecting the grooves wear during the rolling process. The studies were carried out based on the actual engineering data for 160 × 160 mm square cross-section feedstock of steel S355J0. Numerical modelling of the rolling process was performed using Forge2008®, a finite-element based computer program.

Three-Dimensional Analysis of Fluid Flow and Heat Transfer in Single- and Two-Layered Micro-Channel Heat Sinks

2008 ◽  
Author(s):  
M. L.-J. Levac ◽  
H. M. Soliman ◽  
S. J. Ormiston
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Numerical Study ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Micro Channel ◽  
Flow Conditions ◽  
Flow And Heat Transfer ◽  
Computer Chips ◽  
Laminar Flow Conditions

Micro-channel heat sinks are currently at the forefront of cooling technologies for computer chips where the input heat flux is projected to exceed 100 W/cm2 [1, 2]. The quest for better heat-sink designs has produced different ideas, one of which is the idea of using multi-layered micro-channel heat sinks [3, 4]. The objectives of the present investigation were to conduct a detailed numerical study of the hydrodynamic and thermal behavior of a two-layered micro-channel heat sink and to compare the performance of the two-layered heat sink with that of a single-layered sink under laminar flow conditions.

Velocity measurements close to the bed in a wave tank

1970 ◽  
Vol 42 (1) ◽  
pp. 111-123 ◽  
Author(s):  
J. F. A. Sleath
Keyword(s):  
Velocity Distribution ◽  
Vortex Formation ◽  
Reynolds Numbers ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Dominant Effect ◽  
Wave Tank ◽  
High Reynolds Numbers ◽  
High Reynolds ◽  
Laminar Flow Conditions

Measurements of the velocity distribution close to the bed have been made under laminar flow conditions in a wave tank. The classical solution for the velocity distribution was found to be valid when the bed was smooth, but considerable deviations between theory and experiment were observed with beds of sand. It is suggested that these deviations were caused by vortex formation around the grains of sand. The similarity between the velocity profiles obtained in these tests and those reported by other writers under supposedly turbulent conditions suggests that even at high Reynolds numbers vortex formation may continue to be the dominant effect in oscillatory boundary layers of this sort.

scholarly journals Temperature log simulations in high-enthalpy boreholes

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Jia Wang ◽  
Fabian Nitschke ◽  
Maziar Gholami Korzani ◽  
Thomas Kohl
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
Flow Rate ◽  
Fluid Loss ◽  
Flow Conditions ◽  
Flow Rates ◽  
High Enthalpy ◽  
Fluid Losses ◽  
Lateral Heat

Abstract Temperature logs have important applications in the geothermal industry such as the estimation of the static formation temperature (SFT) and the characterization of fluid loss from a borehole. However, the temperature distribution of the wellbore relies on various factors such as wellbore flow conditions, fluid losses, well layout, heat transfer mechanics within the fluid as well as between the wellbore and the surrounding rock formation, etc. In this context, the numerical approach presented in this paper is applied to investigate the influencing parameters/uncertainties in the interpretation of borehole logging data. To this end, synthetic temperature logs representing different well operation conditions were numerically generated using our newly developed wellbore simulator. Our models account for several complex operation scenarios resulting from the requirements of high-enthalpy wells where different flow conditions, such as mud injection with- and without fluid loss and shut-in, occur in the drill string and the annulus. The simulation results reveal that free convective heat transfer plays an important role in the earlier evolution of the shut-in-time temperature; high accuracy SFT estimation is only possible when long-term shut-in measurements are used. Two other simulation scenarios for a well under injection conditions show that applying simple temperature correction methods on the non-shut-in temperature data could lead to large errors for SFT estimation even at very low injection flow rates. Furthermore, the magnitude of the temperature gradient increase depends on the flow rate, the percentage of fluid loss and the lateral heat transfer between the fluid and the rock formation. As indicated by this study, under low fluid losses (< 30%) or relatively higher flow rates (> 20 L/s), the impact of flow rate and the lateral heat transfer on the temperature gradient increase can be ignored. These results provide insights on the key factors influencing the well temperature distribution, which are important for the choice of the drilling data to estimate SFT and the design of the inverse modeling scheme in future studies to determine an accurate SFT profile for the high-enthalpy geothermal environment.

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