An Overview of Heat Transfer Phenomena

doi:10.5772/2623

Cited by 24 publications

(2 citation statements)

References 94 publications

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“…This configuration is similar to the cooling setup of a thin disk laser introduced in Ref. [22,23], in which indium-based or gold-tin solder was used for more efficient heat removal. Since additional heat flow occurs longitudinally from the pump region to the sapphire, reduced temperature rise is expected compared to the case of Fig.…”

Section: Face Cooling Geometrymentioning

confidence: 97%

Cooling Geometry Dependent Operation Properties in a Diode End-Pumped Monolithic Yb:YAG Laser

Moon

Lim

2016

Journal of the Optical Society of Korea

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Operation properties, such as output power, beam radius, and crystal temperature rise were investigated in a diode-pumped edge-cooled monolithic Yb:YAG laser with ~ 4 W pumping level. The output power showed saturation behavior because of severe temperature rise and poor spatial overlapping between pump beam and lasing mode. Face cooling geometry by using a sapphire plate was also investigated. No apparent saturation behavior in output power was observed due to the reduced temperature rise, which could be attributed to efficient heat removal through the crystal-sapphire interface.

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Section: Face Cooling Geometrymentioning

confidence: 97%

Cooling Geometry Dependent Operation Properties in a Diode End-Pumped Monolithic Yb:YAG Laser

Moon

Lim

2016

Journal of the Optical Society of Korea

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“…According to [19,20], the relationship between material resistance and temperature variation has a linear character and can be expressed as:…”

Section: Fig 1 Principal Interpretation Of the Heat Transfer Process ...mentioning

confidence: 99%

Untitled

2024

Engineering, Energy, Transport Aic

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This paper is devoted to a review of the physical principle and effective methodology of thermal anemometry. Its uniqueness lies in the ability to realize a comprehensive high-frequency assessment of the dynamic and thermal state of the turbulent flow. It is worth noting that the American Nobel Prize winner in physics Richard Feynman called turbulence "the most important unsolved problem of classical physics", since there is no direct description of this phenomenon according to classical principles. Therefore, its physical interpretation is still considered one of the six most important mathematical issues of our time. Thus, despite its long history, thermal anemometry remains one of the leading techniques for studying of turbulent flow. Which has a significant impact on hydromechanical and heat-mass exchange processes, particularly in food technology.One of the most common types of thermal anemometry is the Hot-Wire anemometer, where a thin platinum wire is used as a sensor. The principle of operation of the anemometer is to maintain a constant heating of the wire while it is cooled by the surrounding flow of liquid or gas. Thus, the power required to compensate for the thermal state of the sensor wire correlates with the flow rate.The first part of the paper is devoted to the description of the physical principles of thermal anemometry, its advantages and limitations. In particular, special attention is paid to the mathematical interpretation of the heat transfer process between the incremental element of the sensor wire and the surrounding flow. After that, the paper provides a detailed analysis of the design features and practical application of various types of wire sensors. Finally, the last section discusses the calibration methodology and various approaches to the linearization procedure of the obtained calibration curves. Among them, the linearization method based on the Collis-Williams law deserves special attention, since it provides highly accurate interpolation of calibration data and takes into account the temperature compensation of the sensor.

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