مقالات و مطالب لاتین مهندسی مکانیک

EN-EZEL · 6 شهریور، ۱۳۸۸

در خیابان های آمریکا میلیون ها ماشین در حال تردد می باشند و هر کدام از آنها منبع آلودگی هوا می باشند.بالاخص در کلان شهرها میزان آلودگی تولید شده توسط ماشین ها تبدیل به مشکل بزرگی شده بود.

برای حل این مشکل دولت تصمیم به ایجاد قانون هوای پاک برای محدود کردن خودروها در تولید آلودگی کرد.در طی این سالها سازندگان خودرو تغییرات زیادی را در موتور و سیستم سوخت برای اجرای این قانون انجام دادند.یکی از این تغییرات برمی گردد به سال 1975 با یک سیستم ساده و شگفت انگیز به نام مبدل کاتالیزور.کار این سیستم تبدیل آلودگی های بسیار مضر به آلودگی های با ضرر کمتر قبل از این که این آلودگی ها سیستم اگزوز ماشین را ترک کنند می باشد.

در این مقاله شما یاد خواهید گرفت که چه آلودگی هایی توسط موتور ایجاد شده و اینکه این مبدل چه رفتاری با هر یک از این آلودگی ها برای کمک به کاهش ضرر آن ها خواهد داشت.

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EN-EZEL · 6 شهریور، ۱۳۸۸

Abstract

To date, there is no way to explain the process that describes how particles as photon absorb gravitons. According to the results of our years-long research we can definitely say that the best way for explain this process is using color charge concept from photon properties.

This model might be called "Creative Particles of Higgs" or CPH theory. Gravitons behave like charge particles and in interaction between gravity and photons, gravitons convert to negative and positive color charges and also magnetic color. These color charges and magnetic color form the electromagnetic energy.

Keywords: Graviton, Higgs, Photon, color charge, magnetic color, pair production.

1 Introduction

Today’s physics is outspread between macro and micro world. General Theory of Relativity very well describes Macro world, while Quantum Mechanics very well describes probability in micro world. But problem occurs when we want to unify these two theories into the one that would be able to describe each phenomenon in the Universe.

Authors don’t claim that this model is a unified theory of general theory of relativity and quantum mechanics. But authors claim that this is a great step for explaining gravity better than formal quantum theory.

To define graviton, let’s consider to a photon that is falling in the gravitational field, and revert back to the behavior of a photon in the gravitational field. When a photon is falling in the gravitational field, it goes from a low layer to a higher layer density of gravitons. We should assume that the graviton is not a solid sphere without any considerable effect. Graviton carries gravity force, so it is absorbable by other gravitons; in general; gravitons absorb each other and combine.

When some gravitons are around a photon (or other particles) they convert to color charges and enter into the structure of photon. Color charges around particles/objects interact with each other. There exists so much graviton around any particle. There are many layers of gravitons around a photon. The first layer is closed with photon, so that its gravitons interact with charge and magnetic fields in the structure of photon. The second layer interacts with the first layer and third layer and so on. Therefore; when a stone is falling in the gravitational field of the Earth, two layers of gravitons are applied to it, first layer up (at high h) and second down (at high h-dh). In down layer, the density of graviton is greater than up, so the stone falls and its kinetic energy increases.

In this model, an attempt has been made according to the concept of gravitational blue shift, to take the Mössbauer effect, Pound-Rebka experiments and the interaction between gravity and the photon into consideration from a Higgs field point of view. Blue shift and the Mössbauer effect indicate clearly that three different Higgs bosons cause increasing photon mass when they have electromagnetic specifications. This generalizes color charge from the nuclear regime to the photon. This new view of color charge means that we can redefine the graviton and electromagnetic energy.

Gravitons behave like charged particles and in the interaction between gravity and the photon, gravitons convert to negative and positive color charges and magnetic color. These color charges and magnetic color form electromagnetic energy and then electromagnetic energy converts to matter and anti-matter such as charged particles.

Full story PDF format

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EN-EZEL · 6 شهریور، ۱۳۸۸

Bernoulli effect demonstration

Demonstration

The Bernoulli effect results in some unexpected behaviours.

Apparatus and materials

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Rubber tube attached to glass tube with narrow jet

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Air blower

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Polystyrene sphere

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Ping-pong ball

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Glass funnel and tubing

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Cardboard tube (approx 5 cm diameter, 30 cm long)

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Cork ball to fit

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Cardboard tube, small (approx 2.5 cm in diameter, 30 cm long)

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Rubber cord

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Cloth, piece of

Technical notes

A toy air blower will not suffice for these experiments. A cylinder vacuum cleaner with the flexible hose put on the 'blowing' end (as opposed to the 'sucking' end) works well.

ï¿½Jetsï¿½ will have to be made from glass tubing before the lesson.

The cloth should be used to wipe up splashes.

Safety

Read our standard health & safety guidance

Procedure

Ball supported by an air jet

a Blow air down the rubber tubing, on the end of which is a glass tube with a jet at the end. You can support a ping-pong ball or light polystyrene sphere (3 cm diameter), or even a beach ball, on the air flow and it will continue to be 'held' even if the jet is tilted over

Ball supported by an air jet

b You can hold a ping-pong ball similarly in a water jet connected to a water tap. Again, when you tilt the jet the ball will still be supported.

Ball picked up by a funnel

c Connect the glass funnel by rubber tubing to the air blower.

Put the light-weight ball on the table and hold the funnel over it. The air blast through the funnel picks up the ball and holds it.

Experiments involving spin

d Place a light ball, such as a 2.5-cm diameter ball of cork (used by anglers) in a long cardboard tube closed at the lower end. Hold the tube upright by the lower end, with arm stretched up behind your head.

Sweep your out-stretched arm quickly forward and down. The ball rolls out along the upper inside surface of the tube and emerges, spinning fast, around a horizontal axis. The ball's flight then shows a marked curve (upward).

It may help to line the tube with fine sandpaper to make sure the ball rolls rather than slides.

e Fix a length of rubber cord to a bench at two points, A and C. At its centre, B, attach a length of paper tape. Wrap the other end of the tape several times round the middle of a light cardboard cylinder (say, 2.5 cm to 5 cm in diameter and 30 cm long, with its ends closed by paper or Sellotape).

Roll the cylinder along the bench to continue the wrapping until all the tape has been coiled up round it. Then pull the cylinder back across the bench, stretching the elastic cord. Let go of the cylinder so that that the cord catapults it forward. The tape sets it spinning at the same time.

The cylinder will move in a' distorted' path. The Bernoulli effect may even be big enough to make the cylinder loop the loop

Teaching notes

The Bernoulli effect is the reduction in pressure exerted by a fluid due to its flow. In general, the faster the flow the greater the effect.

In step c the flow of air is fastest in the narrow space and so the pressure is less. The greater pressure below supports the ball.

In step d, a spinning ball (or tube) carries the air around with it. As it flies along a projectile's path it has a combined air flow faster above it than below, so the pressure below the ball is higher and the ball rises.

In step a, the flow of air from the centre of the jet is faster, and so the pressure is less. When the jet is tilted, the ball is pushed into the low pressure, so it doesn't fall until the angle becomes too great

EN-EZEL · 6 شهریور، ۱۳۸۸

: Abstract

Inevitable catastrophic fracture that follows accelerated wear of the cutting edges severely deters hard drilling of AISI D2 tool steel. An analysis of stresses induced in the cutting edge attributes such rapid failure to the geometry inherent to drills. The present work hence investigates helical milling of this material, which employs a rotating endmill that traverses a helical trajectory to generate a hole. This innovative method is found to facilitate hole-making in this steel in its hardened state with an order of magnitude enhancement in tool life, under conditions of progressive tool wear. Helical milling is shown to be capable of machining H7 quality holes with a surface finish of 0:3 mmRa such that the need for reaming is eliminated. The process represents an enabling technology with the additional advantage of

being able to accomplish dry cutting, which yields significant environmental and cost benefits

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Siamak · 22 مهر، ۱۳۸۸

ANTI-LOCK BRAKING SYSTEMS (ABS)

Most, if not all, University cars and station wagons are now fitted with ABS brakes. ABS means anti-lock braking system. "What does this have to do with me?", you may ask. Well quite a lot really. ABS brakes could help you to avoid an accident, thus, preventing you from being injured or even saving your life. Unfortunately, safety experts have found that many drivers don't benefit from ABS brakes because the correct techniques for using them are almost the opposite of everything that most of us have been taught about emergency braking in cars. Over the next few weeks we will run a series of hints about using ABS brakes. Please read them carefully. You never know when you might benefit from them.

ABS FACT NUMBER ONE: No matter how hard you brake, ABS prevents the wheels from locking. This means that you can't skid when you brake in an ABS car. This happens because a computer in the car senses the moment when a wheel is about to skid and momentarily releases the brake pressure to that wheel. It then reapplies brake pressure until the wheel is about to skid again when it again releases it. The ABS system is capable of doing this up to 15 times per second, which is much faster than any driver can perform the same task. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER TWO: To get maximum effectiveness from ABS brakes in an emergency, you must continue to brake as hard as you possibly can. Keep your foot hard on the pedal. This is the opposite of the technique which you use in ordinary cars. Remember the ABS system will prevent the wheels from skidding. So KEEP YOUR FOOT HARD ON THE BRAKE PEDAL for as long as you need to do so in order to avoid the obstacle. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER THREE: When you apply the brakes hard in an ABS equipped car, two things will happen. One is that the brake pedal will pulse up and down. The amount of pulsing will vary between cars. The other is that the brakes will make a lot of noise. Don't worry about these things. They indicate that the system is working properly. Just KEEP YOUR FOOT HARD ON THE BRAKE PEDAL for as long as you need to do so in order to avoid the obstacle. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER FOUR: No matter how hard you brake, in an ABS equipped car you can still steer. Why? Because the wheels don't skid, but continue to rotate. This means that you can brake hard to avoid an obstacle and steer around it at the same time. This really adds to your chances of avoiding injury or death. Remember, just STEER NORMALLY, even when braking hard in cars with ABS brakes. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER FIVE: Don't rely on ABS to allow you to drive closer to the car in front or to drive faster. You should continue to maintain a sensible distance between you and the car in front. You should also always drive at a speed which is sensible for the conditions. Always assume that ABS equipped cars will take the same distance to stop as cars which are not equipped with ABS. The big advantage is that the car remains under control. It won't skid and you can still steer it. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER SIX: You may have heard that cars with ABS brakes travel further before stopping on gravel roads than cars without ABS. This does happen with some cars. However, ABS brakes are still an advantage on gravel roads because they prevent the car from skidding and still allow you to steer around the obstacle. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

ABS FACT NUMBER SEVEN: How do I know if a car has ABS brakes? Usually you will find a little sign on the dashboard which says something like ABS. Look for it whenever you pick up a University car so that you know that you are driving a vehicle with this life saving technology. All University cars now have a folder which includes details of the car’s safety and other systems. TAKE THE TIME TO READ IT BEFORE YOU DRIVE AWAY. (Remember, this and the other hints are about emergency braking only. For ordinary braking, ABS brakes operate like ordinary car brakes.)

setarehbaran · 10 اسفند، ۱۳۸۸

Abstract

This paper describes an integrated approach into the design and evaluation of a novel tube bundle heat exchanger that achieves higher heat transfer levels at lower levels of pressure drop, while remaining less susceptible to gas-side fouling. The approach combines laboratory scale experiments with industrial observations and numerical simulations of full-scale heat exchangers to study the thermal, hydraulic and fouling characteristics of tube bundle heat exchangers. Three arrangements are compared and the advantages of the proposed novel arrangement are demonstrated. Enhanced

heat transfer rates are combined with reduced pressure drop and gas-side fouling rates through careful design of the shape of the tube cross-section and reduced transverse spacing

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EN-EZEL · 10 فروردین، ۱۳۸۹

E.E. Gdoutos, "Recent Advances in Experimental Mechanics: In Honor of Isaac M. Danie"

Springer; 1 edition (June 30, 2002) | ISBN: 1402006837 | 844 pages | PDF | 33,6 Mb

This state-of-the-art volume covers a wide range of subjects in experimental mechanics including optical methods of stress analysis (photoelasticity, moiré, etc.), composite materials, sandwich construction, fracture mechanics, fatigue and damage, nondestructive evaluation, dynamic problems, foam, materials, fiber optic sensors, speckle metrology, digital image processing, nanotechnology, neutron diffraction and synchrotron radiation methods. Written by leading scientists in the field, the book contains 71 papers presented at the Symposium on "Recent Advances in Experimental Mechanics", which was organized in honor of Professor I.M. Daniel at Virginia Tech, on June 23-28, 2002. The book presents a thorough review of the latest problems of experimental mechanics. It is a vital supplement and reference source for researchers, practicing engineers and students.

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**M!Zare** · 11 فروردین، ۱۳۸۹

Draft Inducers

Field Draft Inducers solve the drafting problems caused by short chimneys, undersized vent pipes and negative building pressures.

Draft Inducers are designed for easy installation in a wide variety of applications, including oil or gas-fired furnaces, water heaters, and boilers. For venting single or multiple appliances, use a control kit

When to use a Draft Inducer

• Long horizontal vent runs

• Undersized vent pipes

• Short chimneys

• Outside exposed chimney

How Draft Inducers Work

1. Thermostat calls for heat.

2. Control Kit (A) energizes Draft Inducer (B).

3. Draft Inducer forces air flow in chimney, creating negative pressure in burner chamber.

4. Once negative pressure (draft) is established, the Control Kit allows the burner © to start.

5. When the thermostat is satisfied, the Control Kit shuts down the burner and the Draft

**M!Zare** · 11 فروردین، ۱۳۸۹

معادل فارسیه draft inducer لانگستروم میشه؟من تو دیکشنری پیدا نکردم.ولی شکلش خیلی لانگسترومه؟القا کننده هوا هم شاید بشه معنی کرد.به نظر شما کدوم صحیح تره؟

**M!Zare** · 11 فروردین، ۱۳۸۹

Sootblower

Boiler cleaning systems

Steam generating plants are cleaned on-line by regularly removing ash deposits that accumulate on heat transfer surfaces. This maintains maximum thermal efficiency of the boiler (optimizes heat rate) and maintains flue gas temperatures within design conditions at key location. This, in turn, supports the optimum operation of air pollution control equipment. On-line cleaning also prevents the blockage and plugging of gas passages in the boiler.

Cleaning medium

An effective method of on-line boiler cleaning is to direct a concentrated jet of cleaning medium against the soot of ash buildup. The cleaning medium may be saturated steam, superheated steam, compressed air or water. Combinations of water with other media such as steam or air, have also proven effective but can cause boiler tube damage.

Superheated steam is the most widely used medium for several reasons. Boiler-generated steam avoids the cost and maintenance of a compressor. Because it is generally extracted from a high pressure steam outlet and its pressure reduced by regulating valves, steam provides flexibility in case more aggressive cleaning is required. Superheated steam is generally recommended over saturated steam to avoid condensation in the cleaning flow, which can accelerate boiler tube erosion or result in thermal cracking.

Application of sootblowers

The application of sootblowers is individual for each boiler. In general sootblowers are use for cleaning Superheater, Reheater and Economizer.

There are several types of sootblowers like full retractable, half retractable, oscillating and rake type of sootblowers.

The design and layout of sootblowers is individual and specific to meet the installation requirements like flue gas temperature, cleaning effect, cleaning area, etc.

Intelligent Sootblowing enables to use the cleaning force of the sootblowers selectively and targetly according to the demand of the steam generator.

**M!Zare** · 11 فروردین، ۱۳۸۹

Intelligent Sootblowing

Figure 1:

Boiler equipped with cleaning devices like

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and

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and

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like

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.

"Intelligent sootblowing" is a term describing a relatively new approach to on-load boiler cleaning. It applies to the removal of fouling in the in the heat exchanger of boilers, typically in electrical power plants or waste incinerators.

The cleaning is necessary in order to remove fouling that is deposited on the heat exchanger during boiler operation.

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, because of its thermal resistance, acts as an obstruction to heat flow, and dramatically reduces boiler efficiency.

Figure 2:

A real "Intelligent Sootblowing" System is set up in a "Closed Loop" arrangement.

Figure 3:

Fouling in furnace area

Figure 4:

Accumulation of coarse ash in hopper

Fouling and slagging in the furnace as well as in the convective heat exchanger zone leads to a reduction in boiler efficiency and reduction in availanility such as

increase of furnace exit gas temperature

increase of attemperator spray rate

increase of boiler off gas temperature

damages in the hopper area and the wet/dry bottom ash system as a result of big slag formations falling down from the furnace walls or/and superheater

unplanned boiler shut downs

oper-cleaning causes tube damages negatively effecting unit availability

This site offers information about the latest technology and applications.

The main idea behind intelligent sootblowing is that the combination of modern-technology, cleaning devices, sensors and software, the sootblowing process can be dramatically improved, relative to conventional techniques.

These conventional techniques relied on employment of a large number of smaller sootblowing systems, activated by a personal decision of the operator rather than activation based on measurements. The most important result of the employment of more modern systems is that there are possibilities of significant energy savings (present estimates range up to 1 or 2% of the total energy usage), and reduction of downtime.

These saving directly translate into reduced emissions; Intelligent sootblowing therefore is one of the most simple ways of realising reduction of emissions for many electrical power plants.

Secondary benefits are:

Reduction of tube erosion

Reduction of usage of water

Reduction of use of sootblower

Reduction of spray rates (extension of tube lifetime)

Reduction of backpass temperatures.

At present it is estimated by the authors that worldwide about 100 large scale boilers of electrical power plants are equipped with automated 'intelligent sootblowing" systems. These are for some part equipped with sensors for scientific applications, for another part these are commercially operated systems. It is estimated that about 90% of these systems is located in the United States where (forced by the clean air act) intelligent-sootblowing (also called "smart sootblowing") is rapidly becoming accepted practice.

Ariyayi-eng · 13 فروردین، ۱۳۸۹

Nuclear Power Plant Security and Vulnerabilities

Mark Holt

Specialist in Energy Policy

Anthony Andrews

Specialist in Energy and Energy Infrastructure Policy

March 18, 2009

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bahman2 · 16 فروردین، ۱۳۸۹

سلام خسته نباشيد . دو لينك اول كه error ميده . لينك دوم هم پوليه .

EN-EZEL · 16 فروردین، ۱۳۸۹

Photoelasticity has been used for decades to accurately measure surface strains in a strucutre. In this method the test part, complex or not, is first coated with a strain-sensitive plastic coating and then subjected to an external load. The strains which exist throughout the part and over its surface are transferred to the coating and observed as optical interference fringes with a reflection polariscope. Two different paterns are produced with the polariscope -- isochromatics via circular polarization and isoclinics via linear polarization. Isochromatic fringes appear as a series of successive and contiguous different-colored bands each representing a different degree of birefringence corresponding to the underlying strain. The patterns can be read like a topographic map to visualize the stress distribution over the surface of the coated test part. The isoclinic fringes appear as black bands providing the direction of the principal strain.

Zero degree isoclinic image for a hole in plate under vertical tension.

Isochromatic fringes for a hole in plate under vertical tension.

A polariscope positioned in front of a bar with a central hole placed under vertical tension by a hydraulic load frame.

EN-EZEL · 16 فروردین، ۱۳۸۹

Photoelasticity

birefringence - polarization - stress analysis

What it shows:

Normally isotropic substances can become birefringent when under stress. This property can be used in stress analysis.

How it works:

To use birefringence in stress analysis, the sample is placed between two crossed Polaroids. The first Polaroid produces a linearly polarized light source for the sample. This source has components split into ordinary and extraordinary rays; the differing velocities of these rays in the sample creates a phase difference which is color dependant.. The second Polaroid takes components of the ordinary and extraordinary rays; if the components are in phase, constructive interference occurs, and the color is seen. If out of phase, the color is not seen. As the level of birefringence is proportional to the stress, differently stressed areas will appear different colors.

1. A V-shaped piece of thin Plexiglass that can be squeezed to show stress at the elbow.

2. A block of urethane, 10×7×2cm, cast on mercury, that can be squeezed and twisted.

3. Plexiglass block whose holes have been plugged with tightly fitting metal pins. The stress caused the plastic by the insertion of the pins is a model for riveting metal plates in aircraft or ships.

4. C-clamp tightened on a Plexiglass block shows the compressive stress pattern.

The thickness of the material will also dictate which color emerges in phase. Cellophane is drawn in the manufacture of sticky tape, so is birefringent. Because the stress is uniform along its length, it is a single color. We have a sheet of glass with several strips of the tape crisscrossing; here a double layer of tape is a different color because a new color is in phase. Rotate the strips 90° to obtain the complementary colors. Old cellophane bags do the same thing.

Setting it up:

We've found the best way to display is to use two Polaroids

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, one circular (diameter 22cm) that sits on an OHP and the other square (28×20cm) which is on 12cm legs so that it straddles the other. There is space between them so that the sample can be placed and played with. All the above samples are available.

Comments:

Really beautiful colors abound (better when viewed directly so invite your audience up at the end). Clear audio cassette boxes are another good source of stressed plastic. Rating ***

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EN-EZEL · 16 فروردین، ۱۳۸۹

اینهم لینک سالم مقاله بالا

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EN-EZEL · 20 خرداد، ۱۳۸۹

Photogrammetry

What is modal analysis, and photogrammetry?

Let's take a look

All structures experience vibration.

From atoms to stars, everything around us vibrates. Most vibration is perfectly acceptable. In some cases however, it is annoying or even destructive.

Structures vibrate most readily at natural frequencies. The natural frequency depends on the mass and stiffness found within the structure. If a structure receives energy at the same rate as the natural frequency, then a condition called resonance occurs. One of the most famous structural failures due to resonance was the

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in 1940. The source of energy was a steady wind.

To understand, and remedy vibration and resonance problems, it is important to understand how structures vibrate. The motion of a structure due to vibration is called the mode shape. We use modal analysis techniques to understand, and solve structural vibration problems.

MODAL ANALYSIS

This example illustrates two mode shapes for a simple object.

Knowledge of the mode shape allows one to properly address the actual problem. Note how a rib stiffener down the center of the upper and lower plates would help in one case, but in the other case, it wouldn't help at all! In most cases, the correct fix to vibration problems depends on a good understanding of the mode shape.

PHOTOGRAMMETRY

Photogrammetry is the art of taking measurements from photographs.

Using a calibrated camera, we take several photographs of a structure from multiple angles. Photomodeler Pro software

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allows us to quickly create a scaled 3-D model from the photographs. We can rotate the model within the software and observe it from any angle.

The 3-D model is exported to ME'Scope VES software

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to be animated with actual recorded vibration data. We use the animated model to observe the mode shapes.

The example shown here is from an actual study performed by Ball Spin Engineering

In this particular case, before Ball Spin Engineering arrived, a lot of effort was spent investigating foundation resonance. The client drilled holes in the base and added bolts (stiffness modification), they loaded sandbags around the base (mass modification) and tried various other isolation techniques to isolate the problem. Nothing they did seemed to affect the vibration.

The modal analysis took only a few hours to complete. The resulting animation revealed the problem wasn't in the base after all. The problem was actually a lack of stiffness in the motor mounting plate, located nearly 3 meters above the base.

When the motor mount was re-designed with heavier components, the resonance problem disappeared and the pump operated safely within specified vibration limits.

EN-EZEL · 21 خرداد، ۱۳۸۹

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**soheiiil** · 8 مرداد، ۱۳۸۹

pdf files

a course in functional analysis(conway)

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An Introduction To stochastic Differential Equation (LAWRENCE)

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Elementary Differential Equations and Boundary Value Problem(boyce)

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Meshfree Methods for Partial Differential Equations II(geriebel)

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Partial Differential Equations for Engineers and Scientists(Polyanin)

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djvu files

djvu reader program

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Dunford N., Schwartz J. Linear operators. Part 2

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Functional Analysis an introduction eidelman

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Graduate Texts in Mathematics

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Prtial Differential Equations [Lawrence C. Evans]

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**soheiiil** · 14 مرداد، ۱۳۸۹

مقدمه

جریان به عنوان دبی (حجم یا سطح بر واحد زمان) تعریف شده ،که یک ماده از یک سطح مقطع معین عبور میکند و توسط دما و فشار خاص توصیف میشود. ابزاری که برای اندازه گیری جریان استفاده میشود جریان سنج نامیده میشوند(flow meters).قسمتهای اصلی جریان سنج ها شامل حسگر(sensor )، پردازشگر سیگنال و فرستنده می باشد.سنسور های جریان سنج از امواج صوتی و میدان مغناطیسی برای اندازه گیری جریان در یک سطح مقطع معین به وسیله کمیتهای فیزیکی مثل شتاب، فرکانس،فشار و حجم استفاده میکنند. در نتیجه خیلی از جریان سنجها با توجه به خصوصیت فیزیکی که به وسیله آن جریان را اندازه می گیرند نام گذاری می شنود.

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اندازه گیری جریان نقش مهمی در صنایع مختلف از جمله پتروشیمی و صنایع شیمیایی ایفا مکیند.بنابراین اندازه گیری جریان قسمت مهمی از موفقیت یا شکست اقتصادی در هر فرایندی است. مهمتر از این دقت در اندازه گیری جریان این اطمینان را در مورد امنیت پروژه و افرادی که با آن درگیر هستند را به ما میدهد.

انواع معمول جریان سنج ها

دبی جریان که توسط حسگرهای جریان مشخص میشود به وسیله مشخصات فیزیکی تشخیص داده می شود.رابطه بین مشخصات فیزیکی و دبی جریان از اصول مقدماتی جریان سیال بدست می آید مثل معادله برنولی.

انواع جریان سنج هایی که در این مقاله مورد بررسی قرار میگیرند عبارت اند از:

اریفیس، روتامتر، ونتوری متر، جریان سنج توربینی،ملخی، مغناطیسی و انواع جریان سنج فرکانسی.

شما می توانید مقاله ای کامل در مورد حسگرهای جریان را در ادامه مطلب به همراه ترجمه آن دانلود نمایید.

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