Simplified model of airflow and heat transfer in a pallet of food product generating heat

2022 ◽  
Author(s):  
Jean Moureh ◽  
Anh Thu Pham ◽  
Denis Flick
Keyword(s):  
Heat Transfer ◽  
Food Product ◽  
Simplified Model

scholarly journals Effect of buried depth on thermal performance of a vertical U-tube underground heat exchanger

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 327-330
Author(s):  
Li Yang ◽  
Bo Zhang ◽  
Jiří Jaromír Klemeš ◽  
Jie Liu ◽  
Meiyu Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Simplified Model ◽  
Two Dimensional ◽  
Construction Sites ◽  
Full Size ◽  
Unit Depth ◽  
Research Show

Abstract Many researchers numerically investigated U-tube underground heat exchanger using a two-dimensional simplified pipe. However, a simplified model results in large errors compared to the data from construction sites. This research is carried out using a three-dimensional full-size model. A model validation is conducted by comparing with experimental data in summer. This article investigates the effects of fluid velocity and buried depth on the heat exchange rate in a vertical U-tube underground heat exchanger based on fluid–structure coupled simulations. Compared with the results at a flow rate of 0.4 m/s, the results of this research show that the heat transfer per buried depth at 1.0 m/s increases by 123.34%. With the increase of the buried depth from 80 to 140 m, the heat transfer per unit depth decreases by 9.72%.

Figure of Merit-Based Optimization Approach of Phase Change Material-based Composites for Portable Electronics Using Simplified Model

2021 ◽  
Author(s):  
Ayushman Singh ◽  
Srikanth Rangarajan ◽  
Leila Choobineh ◽  
Bahgat Sammakia
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Material ◽  
Figure Of Merit ◽  
Volume Fraction ◽  
Simplified Model ◽  
Transient Temperature ◽  
Change Material

Abstract This work presents an approach to optimally designing a composite with thermal conductivity enhancers (TCEs) infiltrated with phase change material (PCM) based on figure of merit (FOM) for thermal management of portable electronic devices. The FOM defines the balance between effective thermal conductivity and energy storage capacity. In present study, TCEs are in the form of a honeycomb structure. TCEs are often used in conjunction with PCM to enhance the conductivity of the composite medium. Under constrained composite volume, the higher volume fraction of TCEs improves the effective thermal conductivity of the composite, while it reduces the amount of latent heat storage simultaneously. The present work arrives at the optimal design of composite for electronic cooling by maximizing the FOM to resolve the stated trade-off. In this study, the total volume of the composite and the interfacial heat transfer area between the PCM and TCE are constrained for all design points. A benchmarked two-dimensional direct CFD model was employed to investigate the thermal performance of the PCM and TCE composite. Furthermore, assuming conduction-dominated heat transfer in the composite, a simplified effective numerical model that solves the single energy equation with the effective properties of the PCM and TCE has been developed. The effective thermal conductivity of the composite is obtained by minimizing the error between the transient temperature gradient of direct and simplified model by iteratively varying the effective thermal conductivity. The FOM is maximized to find the optimal volume fraction for the present design.

Simplified Thermal Model for Absolute Radiometer Simulation

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Andre Godoi Lopes ◽  
Ricardo Toshiyuki Irita ◽  
Luiz Angelo Berni ◽  
Waldeir Amaral Vilela ◽  
Graziela da Silva Savonov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Thermal Behavior ◽  
Solar Irradiance ◽  
Thermal Model ◽  
Thermal Contact ◽  
Total Solar Irradiance ◽  
Space Environment ◽  
Simplified Model ◽  
Material Volume

Abstract The study of solar radiation in space has become something necessary, motivating the launch of radiometers on board satellites dedicated to perform total solar irradiance (TSI) measurements and to build a record of their behavior over the years, thus making these data essential for meteorology and climatology. In this study, we propose a simplified model to understand the thermal behavior of absolute radiometers, which are used in this type of measurement. The model considers the heat transfer among parts through conduction and loss only by radiation since the instrument operates in a space environment. The goal is to understand how each component interferes with sensitivity and response time of the instrument depending on its design, material, volume, and thermal contact. The model was applied to data generated by a prototype for validation.

scholarly journals All-glass vacuum tube heat transfer simplified model

2019 ◽  
Vol 1386 ◽  
pp. 012095
Author(s):  
O Ardila ◽  
J Quiroga ◽  
O Martínez
Keyword(s):  
Heat Transfer ◽  
Simplified Model ◽  
Vacuum Tube

Internal Temperature Distributions of Vaporizing Droplets: Effect of Their Spacing

2010 ◽  
Author(s):  
G. Castanet ◽  
A. Labergue ◽  
F. Lemoine
Keyword(s):  
Heat Transfer ◽  
Laser Induced Fluorescence ◽  
Simplified Model ◽  
Fluorescence Technique ◽  
Internal Temperature ◽  
Fluid Circulation ◽  
Heat Advection ◽  
Temperature Distributions ◽  
Internal Fluid ◽  
Fuel Evaporation

A line of mono-sized and periodically spaced droplets is moving in the diffusion flame sustained by the droplet fuel evaporation. The temperature field within the droplets is measured using the two-color laser induced fluorescence technique. Experiments are undertaken on droplets made of different fuels including acetone, ethanol, 3-pentanone, n-heptane, n-decane and n-dodecane which have very different volatility and viscosity. A simplified model of the heat transfer within the droplet is developed, taking into account both heat conduction and heat advection by the droplet internal fluid circulation. Streamlines are assumed to follow those of a spherical Hill vortex, the intensity of which can be related to the friction coefficient. Comparisons between the measurements and the simulations reveal that the heat convection within interacting droplets is strongly reduced compared to the model of the isolated droplet.

A Comprehensive Heat Transfer Study Inside a Steam Turbine Valve: Experiment, Numerical Simulation and Simplified Model

2021 ◽  
Author(s):  
Xu Zhang ◽  
Hongyi Shao ◽  
Wenwu Zhou ◽  
Wei Zhe Wang ◽  
YingZheng Liu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Steam Turbine ◽  
Transfer Process ◽  
Electric Heating ◽  
Heating System ◽  
Heat Transfer Process ◽  
Thermal Design ◽  
Simplified Model ◽  
Operational Flexibility

Abstract In a steam turbine system, one of the main factors limiting the operational flexibility is the thermal stress associated with a high temperature gradient within the control valves, which often leads to structural damage during frequent start-up and shut-down cycles. One possible solution is to utilize an electric heating system with appropriate insulation to decrease the warm-up time. Here, an experiment and a numerical simulation were performed using a scaled turbine valve equipped with an electric heating system to understand the heat transfer process. The experiment was conducted at Shanghai Jiao Tong University and had a duration of 100 hours, including three heating-cooling cycles and two heat preservation states. The simulation, which used the commercial software Ansys Fluent 2019 R1 with the finite volume method, was performed to model the experimental heat transfer process. The simulated results showed less than 10% deviation from the measured temperatures. To further improve the computing efficiency, a simplified model based on the lumped parameter method was proposed and validated. This model can predict the valve temperature in less than 1 minute and showed good agreement for all of the studied cases. The ability of the simplified model to simulate the valve heating-cooling cycles at a high efficiency could accelerate the thermal design process to improve the operational flexibility of steam turbines in the future.

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