Radiation in Heat Exchanger & its Analysis

Radiation:

                The process of giving off energy in the form of waves or particles.

  Something that is radiated (as light or X-rays) radiation

                                               

Examples of Radiation:

               Examples include: A burning candle emits radiation in the form of heat and light. The Sun emits radiation in the form of light, heat, and particles

Here are some examples of different types of radiation:

·         Ultraviolet light from the sun.

·         Heat from a stove burner.

·         Visible light from a candle.

·         X-rays from an x-ray machine.

·         Alpha particles emitted from the radioactive decay of uranium.

·         Sound waves from your stereo.

·         Microwaves from a microwave oven

Ionizing radiation:

                                                 

Some kinds of ionizing radiation can be detected in a cloud chamber.

            Radiation with sufficiently high energy can ionize atoms; that is to say it can knock electrons off atoms, creating ions. Ionization occurs when an electron is stripped from an electron shell of the atom, which leaves the atom with a net positive charge. Because living cells and, more importantly, the DNA in those cells can be damaged by this ionization, exposure to ionizing radiation is considered to increase the risk of cancer

Ultraviolet radiation:

           Ultraviolet of wavelengths from 10 nm to 125 nm ionizes air molecules causing it to be strongly absorbed by air and by ozone (O₃) in particular. Ionizing UV therefore does not penetrate Earth's atmosphere to a significant degree and is sometimes referred to as vacuum ultraviolet. Although present in space this part of the UV spectrum is not of biological importance because it does not reach living organisms on Earth.

X-ray:

                    X-rays are electromagnetic waves with a wavelength less than about 10⁻⁹ m (greater than 3x10¹⁷ Hz ). A smaller wavelength corresponds to a higher energy according to the equation E=hc/λ. ("E" is Energy; "h" is Planck's constant; "c" is the speed of light; "λ" is wavelength.) When an X-ray photon collides with an atom the atom may absorb the energy of the photon and boost an electron to a higher orbital level or if the photon is very energetic it may knock an electron from the atom altogether causing the atom to ionize.

Gamma radiation:

                                                           

Gamma radiation detected in an isopropanol cloud chamber.

Gamma (γ) radiation consists of photons with a wavelength less than 3x10⁻¹¹ meters greater than 10¹⁹ Hz. Gamma radiation emission is a nuclear process that occurs to rid an unstable nucleus of excess energy after most nuclear reactions

Alpha radiation:

                                                            

Alpha particle detected in an isopropanol cloud chamber. Alpha particles are helium-4 nuclei (two protons and two neutrons).

Thermal radiations:

                      Heat transfer due to emission of electromagnetic waves is known as thermal radiation. Heat transfer through radiation takes place in form of electromagnetic waves mainly in the infrared region. Radiation emitted by a body is a consequence of thermal agitation of its composing molecules.

°C (°F)	Subjective colour
480 °C (896 °F)	faint red glow
580 °C (1,076 °F)	dark red
730 °C (1,350 °F)	bright red, slightly orange
930 °C (1,710 °F)	bright orange
1,100 °C (2,010 °F)	pale yellowish orange
1,300 °C (2,370 °F)	yellowish white
> 1,400 °C (2,550 °F)	white (yellowish if seen from a distance through atmosphere)

                          

Subjective color to the eye of a black body thermal radiater

Constants:

h {\displaystyle h\,}			Planck's constant		6.626 069 3(11)×10−34 J·s = 4.135 667 43(35)×10−15 eV·s
b {\displaystyle b\,}			Wien's displacement constant		2.897 768 5(51)×10−3 m·K
k B {\displaystyle k_{B}\,}			Boltzmann constant		1.380 650 5(24)×10−23 J·K−1 = 8.617 343 (15)×10−5 eV·K−1
	Stefan–Boltzmann constant			5.670 373 (21)×10−8 W·m−2·K−4
		Speed of light		299 792 458 m·s−1

Uses:

Medicine:

                     Radiation and radioactive substances are used for diagnosis, treatment, and research. X-rays, for example, pass through muscles and other soft tissue but are stopped by dense materials. This property of X-rays enables doctors to find broken bones and to locate cancers that might be growing in the body. Doctors also find certain diseases by injecting a radioactive substance and monitoring the radiation given off as the substance moves through the body. Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing. They don't have as much energy and are not able to ionize cells.

Communication:

                       All modern communication systems use forms of electromagnetic radiation. Variations in the intensity of the radiation represent changes in the sound, pictures, or other information being transmitted. For example, a human voice can be sent as a radio wave or microwave by making the wave vary to corresponding variations in the voice. Musicians have also experimented with gamma signification or using nuclear radiation to produce sound and music.

Science:

                                 Researchers use radioactive atoms to determine the age of materials that were once part of a living organism. The age of such materials can be estimated by measuring the amount of radioactive carbon they contain in a process called radiocarbon dating. Similarly using other radioactive elements the age of rocks and other geological features (even some man-made objects) can be determined this is called radiometric dating. Environmental scientists use radioactive atoms known as tracer atoms to identify the pathways taken by pollutants through the environment.

Radiation is used to determine the composition of materials in a process called neutron activation analysis. In this process scientists bombard a sample of a substance with particles called neutrons. Some of the atoms in the sample absorb neutrons and become radioactive. The scientists can identify the elements in the sample by studying the emitted radiation