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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Tolerance & Fits
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Tolerance
It is defined as, "the magnitude of permissible variation of a dimension or other measured value from the specified value".
Purpose ↠ permit dimensional variations of components, performance, specification and design.
As the permissive tolerance goes on decreasing, the manufacturing cost to achieve it goes on increasing exponentially.
Classification of Tolerance:
Unilateral tolerance ↠ If tolerance distribution is only one side of the basic size.
Bilateral tolerance ↠ When tolerance distribution lies on either side of the basic size.
Compound tolerance ↠ When tolerance is determined by established tolerances on more than one dimensions.
Geometric tolerance ↠ Used to indicate the relationship of one part of an object with another.
Classification of Geometric Tolerance:
Form tolerance ↠ group of geometric tolerance applied to individual features (includes straightness, circularity, flatness, cylindricity).
Orientation tolerance ↠ type of geometric tolerance used to limit the direction/orientation of a feature in relation to other (includes perpendicularity, parallelism, angularity).
Positional tolerance ↠ group of geometric tolerances that controls the extent of derivation of the location of a feature from its true position (includes position, symmetry, concentricity).
Fits
It is defined as, "the relationship between the two mating parts that are to be assembled i.e. the hole and the shaft w.r.t the difference in their dimensions before assembly".
Manufactured parts are required to mate with one another during assembly.
Ideally fits is required for proper functioning of mating parts.
Allowance ↠ intentional difference between the maximum material limits (LLH and HLS) of two mating parts.
Types of Fits:
Clearance Fit ↠ The largest permissible diameter of the shaft is smaller than the diameter of smallest hole.
Interference Fit ↠ The minimum permissible diameter of shaft exceeds the maximum allowable diameter of hole.
Transition Fit ↠ Occurs when two tolerance mating parts are sometimes interference fit and sometimes clearance fit when assembled.
References:
Material from Class Lectures + Book named Fundamentals of Modern Manufacturing Materials, Processes and Systems by Groover + My knowledge.
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
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
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
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