View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
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Vectors
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Vectors:
It is defined as;
Quantity having magnitude and direction are called vectors and they are represented by arrow over the letters.
Types of Vectors:
Types of vectors are as follows:
1. Free Vectors:
Vector having magnitude and direction and can be applied at any point in the space is called Free vector.
2. Sliding Vectors:
Thsee vectors have a line of action in space but no particular point if application
3. Fixed Vectors:
Vectors having specific point of application are called fixed vectors.
Pallelogram Law of Vector Addition:
If two vectors ate considered to be the adjacent sides of a parallelogram, then the resultant of two vectors is given by drawing the diagonal between the vectors.
The formula used for the Parallelogram Law of Vector Addition is:
Resolution of Vectors:
It is defined as;
The converting of a vector into its rectangular components.
1. For 2-dimensional Space:
Now the rectangular componets of vector a are:
ax = a cosθi
ay = a sinθj
And, the rectangular components of vector b are:
bx = b cosαi
by = b sinαj
Now, the resultant X and Y comoments are:
Rx = a cosθi + b cosαi
Ry = a sinθj + b sinαj
And, the resultant vector and angle is given by:
R = √ Rx² + Ry²
ɸ = tan⁻¹ ( Rx / Ry )
2. For 3-dimensional Space:
Where,
Ax, Ay, Az are the projections of vector A
α, β, ɣ are direction cosines
Now, the vector form of vector A is given b:
Vector A = Axi + Ayj + Azk
The magnitude of resultant vector A is given by:
A = √ Ax² + Ay² + Az²
The respective angles are given by:
cosα = vector Ax / A
cosβ = vector Ay / A
cosɣ = vector Az / A
The unit vector is given by:
Unit vector Ua = cosα + cosβ + cosɣ
Or
Vector A = A × (unit vector Ua)
Vector A = Acosα + Acosβ + Acosɣ
And,
A = √ Ax² + Ay² + Az²
A = √ (Acosα)² + (Acosβ)² + (Acosɣ)²
A = A √ (cosα)² + (cosβ)² + (cosɣ)²
cosα² + cosβ² + cosɣ² = 1
Position Vector:
It is defined as;
Vector which specifies the position of point in space is called Position Vector.
Rankine Cycle Rankine cycle is an ideal cycle for Vapour Power Cycles and is normally used for Electricity Generation. The Rankine cycle consist of following steps: 1 ↝ 2 : Isentropic Compression in Pump. 2 ↝ 3 : Constant Pressure Heat Addition in Boiler. 3 ↝ 4 : IsentropicExpansion in Turbine. 4 ↝ 1 : Constant Pressure Heat Rejection in Condenser. Energy Balance: Since, all the devices which Rankine Cycle posses are steady flow devices, so the energy balance for Rankine cycle is: 》For Pump ( q = 0 ): 》For Boiler ( w = 0 ): 》For Turbine ( q = 0 ): 》For condenser ( w = 0 ): The thermal efficiency of Rankine Cycle is: How can we Increase the Efficiency of A Rankine Cycle: The efficiency of a Rankine cycle can be increased: Increasing the avg. temperate at which heat is added Decreasing the avg. Temperature at which heat is rejected. The above two objectives can be achieved by following three methods: 1. By
TAPING CORRECTIONS There are two types of corrections depending upon the type of errors in tape due to the different conditions. 1. Systematic Errors : Slope Erroneous tape length Temperature Tension Sag 2. Random Errors : Slope Alignment Marking & Plumbing Temperature Tension & Sag 1. Temperature Correction It is necessary to apply this correction, since the length of a tape is increased as its temperature is raised, and consequently, the measured distance is too small. It is given by the formula, C t = 𝛼 (T m – T o )L Where, C t = the correction for temperature, in m. 𝛼 = the coefficient of thermal expansion. T m = the mean temperature during measurement. T o = the temperature at which the tape is standardized. L = the measure length in m. For Foot Unit : C t = 6.45×10^-6 (T m – 68 )L For Metric Unit : C t = 1.16
Hydrographic Survey Hydrography is the science which determines the physical features and the navigable portions of the Earth's surface adjoining coastal areas. Surveyors study bodies of water to see what the floor looks like. Techniques and Instruments used in Hydrographic Survey : Many instruments are used in hydrographic survey like multibeam sonars, LIDAR, multibeam echo sounders(MBES), global positioning system (GPS), laser scanners etc. Among these instruments some are discussed ahead which are mostly used. 1. Light Detection and Ranging: LIDAR is used to measure the elevation or the depths of water bodies by analyzing the reflection of laser light off an object or seafloor. Bathymetric LIDAR is used to determine is used to determine the depths of water bodies by measuring the time delay between the pulse of transmission and its return signals. 2.Multibeam Sonars: Multibeam echo sounders(MBES) or sonar systems transmit sound energy which strike seafloor a
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