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The expansion of steam in an ideal nozzle is isentropic, which is accompanied by condensation process. If the steam is initially superheated, the condensation should start after it has become dry saturation. The flow of supersaturated steam, through the nozzle is called supersaturated flow or metastable flow.
What is degree of undercooling in nozzle?
The steam nozzle. supercooled and the degree of supercooling is given by (t2- IR). Sometimes a degree of supersaturation is defined as the ratio of the actual pressure Pż to the saturation pressure corresponding to the temperature tr. It can be seen from Fig.
What do you understand by supersaturated flow in the nozzle?
When steam expands in a nozzel it’s pressure drops and temperature goes down. At steams velocity it does not stay in the valve long enough to properly transfer enough heat and water condensation is held up. This is dry super saturated steam in a region where it should be wet is supersaturated nozzle flow.
What are the effects of super saturation in steam nozzle?
Thus the effect of supersaturation is to reduce the enthalpy drop slightly during the expansion and consequently a corresponding reduction in final velocity. The final dryness fraction and entropy are also increased and the measured discharge is greater than that theoretically calculated.
Why supersaturated phenomenon occurs in nozzle and what are its effects?
The supersaturation phenomenon occurs in the nozzle due to delay in condensation as a result of which mass flow rate coming from the nozzle is more than the designed value. The expansion of superheated stem from pressure P1 to Pb is represented by the line AB.
What is steam nozzle?
The steam nozzle is a passage of varying cross-section by means of which a part of the enthalpy of steam is converted into kinetic energy as the steam expands from a higher pressure to a lower pressure. Therefore, a nozzle is a device designed to increase the velocity of steam.
What is a nozzle?
1a : a projecting vent of something. b : a short tube with a taper or constriction used (as on a hose) to speed up or direct a flow of fluid. c : a part in a rocket engine that accelerates the exhaust gases from the combustion chamber to a high velocity.
What are the effect of supersaturation flow?
The Supersaturation reduces the heat drop (for the same pressure limits) below that for thermal equilibrium. Hence the exit velocity of the steam is reduced. 4. The Supersaturation increases dryness fraction of steam.
How does steam flow through nozzles?
The flow of steam through nozzles may be regarded as adiabatic expansion. – The steamhas a very high velocity at the end of the expansion, and the enthalpy decreases as expansion takes place. – Friction exists between the steam and the sides of the nozzle; heat is produced as the result of the resistance to the flow.
Which nozzle is used in rocket engine?
The main type of rocket engine nozzles used in modern rocket engines is the de Laval nozzle which is used to expand and accelerate the combustion gases, from burning propellants, so that the exhaust gases exiting the nozzles are at hypersonic velocities.
What is the condition for maximum discharge through a steam nozzle?
When steam expands in a nozzle, if the internal energy given up is entirely used in adding to the kinetic energy of the stream, there is, for a given initial pressure, one lower pressure at which the product of the velocity and density of the stream is a maximum.
What is the effect of friction on the flow through a steam nozzle?
in case of nozzle, friction will decrease the motion of flow, that is friction will decrease the velocity of floor. as a result, actual velocity of flow would be less than theoretical velocity of flow through nozzle.
How do you calculate flow rate of a nozzle?
3 Flow rate Any nozzle will produce certain flow rate at a given pressure differential. The flow rate for a given nozzle can be calculate by the following formula. Q= Flow rate. K = K factor for nozzle. P = Pressure differential at the nozzle. n = Is a constant that depends upon the spray pattern type.
Why nozzles are made convergent and divergent?
Convergent-divergent type of nozzles are mostly used for supersonic flows because it is impossible to create supersonic flows (mach number more than one) in convergent type of nozzle and therefore it restricts us to a limited amount of mass flow through a particular nozzle.
What is the function of steam nozzle?
Steam nozzle is an insulated passage of varying cross-sectional area through which heat energy (Enthalpy), pressure of steam is converted into kinetic energy. 1) The main function of the steam nozzle is to convert heat energy to kinetic energy.
What is the use of nozzle?
A nozzle is a device designed to control the direction or characteristics of a fluid flow (especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid (liquid or gas).
Why nozzle is used in steam turbine?
A steam nozzle is a passage of varying cross-sections, which converts the heat energy of steam into kinetic energy. The main use of a steam nozzle is in a steam turbine, which produces a jet of steam with a high velocity. No heat is supplied or rejected by the steam during flow through a nozzle.
What are the different types of steam nozzles?
Three important types of steam nozzles are:- 1) Convergent Nozzle, 2) Divergent Nozzle, 3) Convergent-Divergent Nozzle.
What are the types of nozzle?
Nozzle Nozzle. The Nozzle Tip is one of the most important and least expensive part of a spraying system. Adjustable nozzle. Double swirl spray nozzle. Selecting a spray nozzle. Hollow cone nozzles-Disc and core type. Flat fan nozzles. Floodjet nozzles. Adjustable nozzles.
What is the cost of nozzle?
Questions & Answers on Spray Nozzles Material Min Price Max Price Brass Rs 90/Piece Rs 1330/Piece Stainless Steel Rs 135/Piece Rs 600/Piece ABS Plastic Rs 150/Piece Rs 250/Piece PVC Rs 60/Piece Rs 600/Piece.
Does nozzle reduce pressure?
The pressure drops in a convergent nozzle because of the Bernoulli Principle. A nozzle is a spout on the end of a hose or pipe used to control the movement of a fluid like water or air. In this case, the energy that causes pressure is converted to another type of energy, so both pressure and area decrease.
What is fuel nozzle?
The pressure-atomizing unit that receives fuel under high pressure from the fuel manifold and delivers it to the combustor in a highly atomized, and precisely patterned spray.
