Process control is the act of controlling a final control element to change the manipulated variable to maintain the process variable at a desired set point. Lectures in computational fluid dynamics of incompressible flow. Throttling devices expansion valves in refrigeration, air. Similarly, if the discharge side system resistance will increase due to discharge valve throttling. What is the theory of combined separating and throttling. Computer networks unit iii y3s5 dept of cse,rgcet page 5 for example, in fig. In general, cooling is a heat transfer process down a temperature gradient, it can be a. Aug 15, 2007 the throttling process is controlled either manually or better yet, with a control valve. Centrifugal pump problems 5 overview of pump problems typically found on centrifugal pumps. Lecture 14 ideal gas law and terms of the motion of molecules. For a given change in the manipulated variable the process variable must. How to download all of the lectures for a course in nptel. However, a typical control strategy for such a process would use only 4 of these feedrate, column pressure, top and bottom composition.
However, a typical control strategy for such a process would use only 4 of these. How to download all of the lectures for a course in nptel quora. Sep 25, 2016 throttling and separating calorimeters are used to measure the dryness fraction of steam. Enthalpy, entropy, mollier diagram and steam tables course no. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. Throttling process is the irreversible steady flow expansion process in which perfect gas is expanded through the orifice of minute dimensions like the narrow throat of the slightly opened valve. Throttling process in hindi thermodynamics by d verma sir duration. Manufacturing processes i nptel online videos, courses. The nozzles are of converging or diverging or convergingdiverging type as per the design. As stated in chapter 2, a vapour is a partially evaporated liquid carrying in it particles of liquid and it can be liquefied by minor changes in temperature or pressure. An example of a throttling process is an ideal gas flowing. Nguyen, chemical and materials engineering, cal poly pomona.
Thermodynamics enthalpy entropy mollier and steam tables i. Nptel, an elearning initiative by the 7 indian institutes of technology and the indian institute of science with the support of the mhrd, govt. Feb 27, 2018 throttling process in hindi thermodynamics by d verma sir duration. Throttling has been mentioned as a constant enthalpy process in thermodynamics book. If the steam is sufficiently dry to enable it to reach a supersaturated state by throttling process, then a solitary throttling calorimeter can serve the pur. After throttling to evaporator pressure, the heat transfer in the evaporator causes vaporization of the working medium until state 1 is reached, thus completing the cycle. Vortex tube refrigeration it consists of nozzle, diaphragm, valve, hotair side, coldair side. Throttling process a throttling process is defined as a process in which there is no change in enthalpy from state one to state two, h 1 h 2. A throttling process is one in which the fluid is made to flow through a restriction, e. During the throttling process no work is done by or on the system dw 0, and usually there is no heat tranfer. Pumps and pumping system bureau of energy efficiency 116 figure 6.
It means both system and surroundings are returned to their initial states at the end of the reverse process. In an ideal cycle it can d is an expansion process. It is used as the working substance in the operation of steam engines and steam turbines. In software, a throttling process, or a throttling controller as it is sometimes called, is a process responsible for regulating the rate at which application processing is conducted, either statically or dynamically. So, you want to download all of the video lectures for a course in nptel. Why enthalpy remain constant in throttling process.
A throttling process is defined as a process in which there is no change in enthalpy from state one to state two, h1 h2. Throttling and separating calorimeters are used to measure the dryness fraction of steam. But avoid asking for help, clarification, or responding to other answers. Different types of valves used in piping a complete guide. During the throttling process no work is done by or on the system dw 0, and usually there is no heat tranfer adiabatic from or into the system dq 0. K 2082012 1 syllabus subject basic thermodynamics sub. Figure 1 degrees of freedom analysis of distillation column. Reversible and irreversible process a reversible process is defined as a process that can be reversed without leaving any trace on the surroundings. Estimate heat and work transferred in various thermodynamic processes.
V i for an ideal gas undergoing any reversible thermodynamic process. Chemical engineering thermodynamics course notes download book. The vapor compression refrigeration cycle involves four components. A throttling process is a thermodynamic process, in which the enthalpy of the gas or medium remains constant h const. An efficient nozzle is designed to have higher velocity, greater mass flow and minimum inlet losses. The vapor compression refrigeration cycle, step by step. But i was wondering how does the industry actually usesimplements this technique, in term of getting to a desired state point in a system. Joule thomson coefficient derivation physics stack exchange. In fact, the throttling process is one of isenthalpic processes. From hs or even ts diagram, i can see how pressure is dropped and you reach another. The temperature change pertaining to the joulethomson effect can occur when a flowing gas passes through a pressure regulator, which acts as a throttling device, valve, or porous plug.
Process control and instrumentation nptel online videos. The pressure developed by the compressor will increase and flow rate will start decreases. The refrigerant leaves the compressor at high pressure and temperature and enters the condenser. Steam is generated in boilers at constant pressure. Classification of valvesthe following are some of the commonly used valve classifications, based onmechanical motion. These operations are performed mainly by using electrical machines or diesel, petrol and steam engines as a prime mover. Computational fluid dynamics of incompressible flow. To balance out any joulethomson related temperature changes, a heating or cooling element can be used. One is to pass air at constant secondary pressure, regardless of the flow variation or upstream pressure and the other is to reduce the pressure to a level that meets with work requirements, minimizing the amount of wasted pressurized air. Feb 17, 20 why enthalpy remain constant in throttling process. In this article, i have covered classifications of valves and functions of valves.
Following conditions are necessary for combustion to take pfollowing conditions are necessary for combus tion to take placetion to. Temperature of process steam typically increases from around 175c to 235c. Lecture 14 ideal gas law and terms of the motion of. Hence, it could be used as a working substance for heat engines. Centrifugal compressor surgebasics, mechanism mechanical. At lower at lower load and higher throttle, the initial and final pressure and higher throttle, the initial and final pressure oof. Refrigerants data refrigerant he3 he4 h 2 d 2 ne n 2 co f 2 helium helium hydrogen deuterium neon nitrogen carbon fluorine monoxide temperatures k liq liq 2phase equilibrium at 10 mbar 0. After leaving the condenser the refrigerant is at medium temperature and high pressure and then it enters the throttling valve. Wnrtln v f v i for a constant temperature process wpdv v i. Valve is a device that regulates, controls or directs the flow of a fluid by opening. In software, a throttling process, or a throttling controller as it is sometimes called, is a process responsible for regulating the rate at which application processing is conducted, either statically or dynamically for example, in high throughput processing scenarios, as may be common in online transactional processing architectures, a throttling controller may be embedded in the. Throttling devices are another vital parts of all the refrigeration systems and air conditioning systems apart from the compressor, condenser and the evaporator. The gascooling throttling process is commonly exploited in refrigeration processes such as air conditioners, heat pumps, and liquefiers. Throttling process isenthalpic process nuclear power.
Here, a temperature change is not necessarily desirable. To better understand the theory of the ideal throttling process lets compare what we can observe with the above theoretical assumptions. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Before explaining how the throttling calorimeter works we first explain the process of throttling in some detail. A corollary to the definition of process control is a controllable process must behave in a predictable manner. Thanks for contributing an answer to physics stack exchange. The same phenomena will happen, that is the operating point a shifted to the new operating point of b. Total streams 8 extra phases 3 degrees of freedom 5 so the number of degrees of freedom is 5. It is a compression process, whose aim is to raise the refrigerant pressure, as it flows from an evaporator. Mcdonough departments of mechanical engineering and mathematics. Mcdonough departments of mechanical engineering and mathematics university of kentucky c 1991, 2003, 2007. Introduction the controlled movement of parts or a controlled application of force is a common requirement in the industries. Four situations where the work done by an ideal gas is very clear.
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