CFD - Tool of Engineers.

Here comes ma first post in this blog. I just wanna make my first post about something which people are not much aware of. So I am jus penning here, a very brief introduction of CFD. Hope people will get a lucid picture about CFD from this post.
COMPUTATIONAL FLUID DYNAMICS:
What is CFD?
Computational Fluid Dynamics (CFD) is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as chemical reactions by means of computer-based simulation. The technique is very powerful and spans a wide range of industrial and spans a wide range of industrial and non-industrial application areas.
How does a CFD code work?
CFD codes are structured around the numerical algorithms that can tackle fluid flow problems. All codes contain three main elements: (1) a pre-processor (2) a solver (3) a post-processor
PRE-PROCESSOR:
Pre-processor consists of the input of a flow problem to a CFD program by means of an operator-friendly interface and the subsequent transformation of this input into a form suitable for use by the solver. Pre processing stage involves fixing the domain, Generation of grids, Selection of physical and chemical phenomena, Definition of fluid properties, and Specification of appropriate boundary conditions
SOLVER:
There are three distinct streams of numerical solution techniques. Finite difference, finite element and spectral methods. The numerical methods that form the basis of solver perform the following steps.
1. Approximation of the unknown flow variables by means of simple functions
2. Discretisation by substitution of the approximations into the governing flow equations and subsequent mathematical manipulations
3. Solution of the algebraic equations
4. The main differences between the three separate streams are associated with the way in which the flow variables are approximated and with the discretisation process
POST-PROCESSOR:
As in pre-processing a huge amount of development work has recently taken place in the post-processing field. Owing to the increased popularity of engineering workstations, many of which have outstanding graphics capabilities, the leading CFD packages are now equipped with versatile data visualization tools. These include vector plots, line and shaded contour plots, 2D and 3D plots etc
APPLICATIONS:
CFD software gives us the power to simulate flows of gases and liquids, heat and mass transfer, moving bodies, multiphase physics, chemical reaction, fluid-structure interaction and acoustics through computer modeling. Since it builds a 'virtual prototype' of the system or device that we wish to analyze, it makes our work bit easy and of course with perfection. The software will provide us with images and data, which predict the performance of that design.

Gate solution 2009

Solved by Jai kumar,Jhangra D.Crust (Hariyana)
1 -C 21-A 41-A
2 -C 22-D 42- A
3 -C 23-C 43-A
4 -B 24-D 44-D
5 -D 25-B 45-C
6 -A 26-A 46-----
7 -D 27-A 47-D
8 -D 28-B 48-A
9 -A 29-D 49----
10-B 30-B 50-D
11-C 31-B 51-C
12 -B 32-B 52-D
13-C 33-B 53-A
14 -C 34-C 54-D
15 -A 35-B 55-C
16 -D 36-B 56-C
17-D 37-A 57-D
18 -C 38-B 58-D
19 -A 39-C 59- C
20 -A 40-B 60-B

Solar Radiation Measurements

Instruments for measuring solar radiation:
Two basic types of instruments are used in measurements of solar radiation. These are:
1. Pyranometer: An instrument used to measure global (direct and diffuse) solar radiation on a surface. This instrument can also be used to measure the diffuse radiation by blocking out the direct radiation with a shadow band.
2. Pyrheliometer: This instrument is used to measure only the direct solar radiation on a surface normal to the incident beam. It is generally used with a tracking mount to keep it aligned with the sun.

  
Solar radiation defining terms:
Diffuse radiation: Scattered solar radiation coming from the sky.
Direct or beam normal radiation: Part of solar radiation coming from the direction of the sun on a surface normal to the sun’s rays.
Equation of time: Correction factor in minutes, to account for the irregularity of the Earth’s motion around the sun.
Extraterrestrial solar radiation: Solar radiation outside Earth’s atmosphere.
Insolation: Incident solar radiation measured as W/m2 or Btu/hr-ft2.
Solar altitude angle: Angle between the solar rays and the horizontal plane.
Solar azimuth angle: Angle between the true south horizontal line and the horizontal projection of the sun’s rays.
Solar constant: Extraterrestrial solar radiation at the mean Earth-sun distance.
Solar declination: Angle between the Earth-sun line and a plane through the equator.

Electrical Process Tomography

Electrical Tomography is a measurement technique for obtaining information about the contents of process vessels and pipelines. Multiple electrodes are arranged around the boundary of the vessel at fixed locations in such a way that they do not affect the flow or movement of materials. Tomographic measurement techniques differ from point measurement techniques, because they sample a substantial proportion of the process volume rather than at a single point. Circular pipeline-based sensors measure an entire cross-sectional volume. 

The technology can be used for liquid/liquid, solid/ liquid, gas/liquid, gas/solid/liquid systems. The spatial resolution of the imaging method and the sensitivity of the method depend specifically on the electrical properties of the system being measured and upon the dimensions of the process.

Typically, a sensor consists of 16 electrodes and for research applications up to 8 x 16 electrodes may be arranged within a process vessel.

The technique can be used with a wide range of research and development applications demonstrated, including:
1. interrogation of mixing processes 
2. investigating a solid-liquid filtration process 
3. monitoring the performance of a hydrocyclone 
4. measurement and control of bubble columns 
5. measurement of multiphase flow 

One of the main application areas of electrical tomography is the measurement of multiphase flow regimes.

Flow processes may involve a variety of phases or components in the gas, liquid or solid phase and are complex in their nature. Electrical tomography techniques provide the capability for flow visualisation, regardless of material opacity, to enhance the understanding of such complex flow processes.

Why is Stainless Steel Stainless?

An English Metallurgist, working on a project to improve rifle barrels, accidentally discovered that adding chromium to low carbon steel gives it stain resistance.In addition to iron,carbon and chromium, modern stainless steel may also contain other elements such as nickel, niobium, molybdenum and titanium.Nickel, molybdenum, niobium and chromium enhance the corrosion resistance of stainless steel.Its the addition of a minimum 12% of chromium to the steel that makes it resist rust, or stain 'less' than other types of  steel.The chromium in the steel combines with oxygen in the atmosphere to form a thin, invisible layer of chrome-containing oxide, called the passive film.The sizes of chromium atoms and their oxides are similar, so they pack neatly together on the surface of a metal,forming a stable layer only a few atoms thick.If the metal is cut or scratched and the passive film is disrupted, more oxide will form quickly and recover the exposed surface, protecting it from the oxidation corrosion.Iron, on the other hand rusts very quickly because atomic iron is much smaller than its oxide.The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistances in low-oxygen and poor circulation environments.

Coconut Shell Ash - A Novel Adsorbent

Coconut shell activated carbon exhibits good adsorption characteristics and can be used as a low-cost adsorbent for COD removal from distillery spent wash.One of the main advantage of using coconut ash over the other chemical treatment methods is that it is in abundance and its easy availability makes it a strong choice in the investigation of economic way of COD removal.

How to prepare?

1. The shells derived from various waste sources were cleanly shaved to remove all the fibres on its surfaces.
2. Cleaned shells were cut into 3 mm to 8 mm pieces.
3. These pieces were washed with distilled water to remove dust and dried in sunlight for 2-3 days.
4. The cleaned and dried coconut shells were then broken into small pieces to allow insertion into a muffle furnace(KW=0.3,AMP=13,TYPE=MFRA,PHASE=SINGLE)and subjected to destructive distillation in the absence of air.
5. The temperature of the furnace was maintained up to 400 C for three hours to avoid reactions with atmospheric oxygen and thereby preventing formation of ash.
6. The resulting carbonized matter was washed with water and dried at 100 C.
7. The dried material was grounded and sieved to separate particles of 20-50 Mesh(ASTM)with the help of standard sieves.
   

Now the adsorbent is ready and those interested in doing their projects in WASTE WATER TREATMENT can use this as an alternative for other chemical adsorbents.

IGIOGT

Indo Gulf Institute of Oil and Gas Technology is the first Premier Training Institute offering short and long term basic.foundation and advance level practical job oriented training programmes on topics related to Oil & Gas sector.IGI has tie up with many Oil & Gas Companies in India as well as globally.IGI was started in 2006 and has a good placement record since then.Candidates above 20 years of age who have completed Engineering degree in Chemical,Mechanical,E & I,Petroleum & Petrochemical,C & I.For more details,check out the link www.igiog.in

Dr Richard Seligman's Invention

The plate heat exchanger (PHE) was invented by Dr Richard Seligman in 1923. This type of exchanger consists of parallel plate held firmly together between substantial head frames. These plates serve as the heat transfer surfaces. The design principle is as simple as the other plate and frame equipments. The plates are pressed, corrugated metals fitted between a thick, carbon steel frame. The presence of the corrugated plates provides a higher degree of turbulence even at low flow rates. Each plate flow channel is sealed with a gasket, a weld, or an alternating combination of the two. The advantages of this type of heat exchangers are low pressure drops, absence of interleakage of fluids, ease in cleaning and dismantling and high heat transfer coefficients.

BARC

Ho my dear dudes and dudettes!! there is a chance for you people to enter BARC as a training school canditate. Online application form for this is available in the site address given below. Last date is not mentioned clearly so the sooner the better.
www.npcil.co.in/hrdbarc/oces.htm
Gate is not necessary for this. If you have not written gate no problem. They have a separe exam for this. First exam and then its followed by interview.
Once you enter training school you will be posted as a scientific officer. Good luck!!!!

TUNGSTEN

Symbol : W
Other name : wolfrum
Atomic Number : 74
Atomic weight : 183.84
Melting point : 3695 K
Boiling point : 5828 K
Oxidation state : +6

Tungsten came into existence due to the works of Scheele, who found a new acid "tungstenic acid", later José and Fausto Elhuyar brothers successfully reduced it with the help of the charcoal and a new metal was invented. It was initially used in World War II for the weaponry industry. Occurring in steel gray to white metal color, it has a very high melting point after carbon. There 5 natural isotopes, with 30 artificial isotopes. Tungsten has the lowest vapor pressure, highest tensile strength and the lowest coefficient of thermal expansion of any pure metal. It is an essential nutrient for some organisms and the only metal known to occur in the biomolecules.
Tungsten has a wide range of uses, mainly in high temperature applications. These include light bulb, cathode-ray tube, vacuum tube filaments, and heating elements, nozzles on rocket engines, welding applications and in the gas tungsten arc welding process (also called TIG welding). Tungsten is also used in electrodes, in the emitter tips of field emission electron-beam instruments, such as focused ion beam (FIB) and electron microscopes, as an interconnect materials in ICs, manufacture of metallic films, X-ray targets, and shielding from high-energy radiations. Tungsten powder is used as a filler material in plastic composites, a nontoxic substitute for lead in bullets, shot, and radiation shields. Tungsten alloys play a major role due to their hardness and density. Superalloys like Hastelloy and Stellite, are used in turbine blades and wear resistant parts and coatings. High-density alloys of tungsten are used in darts or for fishing lures. Some types of strings for musical instruments are wound with tungsten wires. It also used in jewelry, glass to metal seals, a catalyst, high-temperature lubricants (WS2) and wear-resistant abrasives and cutters (WC). Tungsten oxides are used in ceramic glazes, calcium/magnesium tungstates are used widely in fluorescent lighting and inorganic pigments. Crystal tungstates are used as scintillation detectors in nuclear physics and nuclear medicine. Other salts that contain tungsten are used in the chemical and tanning industries.