Thermal Radiation Heat Transfer

John R. Howell, M. Pinar Mengüc, Kyle Daun, Robert Siegel

• Editore: CRC Press
• Anno: 2020
• ISBN:
  9781000257830
• Edizione: 7
• Argomento: Physical Sciences
• Categoria: Energy

The seventh edition of this classic text outlines the fundamental physical principles of thermal radiation, as well as analytical and numerical techniques for quantifying radiative transfer between surfaces and within participating media. The textbook includes newly expanded sections on surface properties, electromagnetic theory, scattering and absorption of particles, and near-field radiative transfer, and emphasizes the broader connections to thermodynamic principles. Sections on inverse analysis and Monte Carlo methods have been enhanced and updated to reflect current research developments, along with new material on manufacturing, renewable energy, climate change, building energy efficiency, and biomedical applications.

Features:

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• Offers full treatment of radiative transfer and radiation exchange in enclosures.

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• Covers properties of surfaces and gaseous media, and radiative transfer equation development and solutions.

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• Includes expanded coverage of inverse methods, electromagnetic theory, Monte Carlo methods, and scattering and absorption by particles.

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• Features expanded coverage of near-field radiative transfer theory and applications.

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• Discusses electromagnetic wave theory and how it is applied to thermal radiation transfer.

This textbook is ideal for Professors and students involved in first-year or advanced graduate courses/modules in Radiative Heat Transfer in engineering programs. In addition, professional engineers, scientists and researchers working in heat transfer, energy engineering, aerospace and nuclear technology will find this an invaluable professional resource.

Over 350 surface configuration factors are available online, many with online calculation capability. Online appendices provide information on related areas such as combustion, radiation in porous media, numerical methods, and biographies of important figures in the history of the field. A Solutions Manual is available for instructors adopting the text.

1 Introduction to Radiative Transfer

Wilhelm Carl Werner Otto Fritz Franz (Willy) Wien (1864–1928) studied mathematics and physics at the Universities of Göttingen and Berlin. In 1886, he completed his doctorate with a thesis on diffraction and how materials impact the color of refracted light. In 1893, he announced the Law of Displacement, which states that the product of wavelength and absolute temperature for a blackbody is constant. In 1896, he proposed a formula which described the spectral composition of radiation from an ideal body, which he called a blackbody. This work earned Wien the 1911 Nobel Prize in Physics, and later impelled Max Planck to propose quantum effects to bring Wien’s distribution into agreement with experimental measurements.

Max Planck (1858–1947) arguably laid the basis for quantum mechanics and was one of the forerunners of modern physics. He originally developed his blackbody spectral distribution based on the observation that the denominator in classically derived distributions such as that of Wien needed to be slightly smaller to fit the experimental data. His attempts to explain the theoretical basis of his proposed spectral energy equation led him to hypothesize the existance of quantized energy levels, a concept that was at odds with all of classical physics and thermodynamics. He was forced to accept Boltzmann’s statistial interpretation of the Second Law of Thermodynamics, as opposed to the more classical deterministic view.

Energy radiates from all types of matter under all conditions and at all times. The emission of thermal radiation arises from random fluctuations in the quantized internal energy states of the emitting matter. Temperature is a measure of the internal energy level of matter, and the nature of the fluctuations can be related to an object’s temperature. Once the energy is radiated, it propagates as an electromagnetic (EM) wave. If the waves encounter matter, they may partially lose their energy and increase the internal energy of the receiving matter. This is called absorption. The amount of emitted and absorbed radiation are functions of the physical and chemical properties of the material as well as its internal energy level, as quantified by its temperature.

An EM wave can also undergo scattering as it propagates through a heterogeneous medium, e.g., a porous ceramic, a layer of freshly fallen snow or even the molecules in a gas. As waves encounter these scattering centers, they are reflected, refracted, or diffracted, or any combination of these phenomena, which redirects the wave without increasing the internal energy of the scatterer. The propagation and scattering of EM waves, including all effects of reflection, refraction, transmission, polarization and coherence, are governed by the Maxwell equations, as we discuss in Chapters 8, 10, and 16.

Since all matter emits and absorbs radiation under all conditions, there is always radiative transfer of energy, even within an isothermal system. If two objects are at different temperatures, there will be net radiation energy transfer between them, even if there is no matter between the objects. An obvious example is radiation emitted by the sun, which travels through the vacuum of space and is partially absorbed and scattered upon entering the earth’s atmosphere. A significant part of this radiation reaches the earth’s surface, where again, some is absorbed and some is reflected (Figure 1.1). These three distinct physical mechanisms – emission, absorption, and scattering – are all spectral in nature; that is, they all depend on the wavelength or frequency of the EM wave. Global warming, for example, is driven by spectral variations in the radiation emitted by the sun, the radiation emitted by the earth, and the fact that the atmosphere absorbs and scat...