Non Newtonian Fluid Mechanics

Posted by admin on October 31, 2009 under Fluid Mechanics | Be the First to Comment

A non-Newtonian fluid is a fluid whose flow properties are not described by a single constant value of viscosity. Many polymer solutions and molten polymers are non-Newtonian fluids, as are many commonly found substances such as ketchup, starch suspensions, paint, blood and shampoo. In a Newtonian fluid, the relation between the shear stress and the strain rate is linear (and if one were to plot this relationship, it would pass through the origin), the constant of proportionality being the coefficient of viscosity.

In a non-Newtonian fluid, the relation between the shear stress and the strain rate is nonlinear, and can even be time-dependent. Therefore a constant coefficient of viscosity cannot be defined. A ratio between shear stress and rate of strain (or shear-dependent viscosity) can be defined, this concept being more useful for fluids without time-dependent behavior.

Reference – Non Newtonian Fluid Mechanics at Wikipedia

Websites on Non Newtonian Fluid Mechanics

1. Journal of Non-Newtonian Fluid Mechanics – Elsevier – Journal of Non-Newtonian Fluid Mechanics
2. Non-Newtonian fluid: Definition from Answers.com – non-Newtonian fluid (fluid mechanics ) A fluid whose flow behavior departs from that of a Newtonian fluid, so that the rate …
3. Highlights in Non-Newtonian Fluid Mechanics – Highlights in Non-Newtonian Fluid Mechanics
4. Fluid mechanics of tape casting a non-Newtonian fluid – Fluid mechanics of tape casting a non-Newtonian fluid
5. Principles of non-Newtonian fluid mechanics (Open Library) – Principles of non-Newtonian fluid mechanics
6. A pool filled with non-newtonian fluid – Youtube Video
7. Non-Newtonian Fluid Mechanics and Microfluidics – Know more about Microfluidics
8. Dimensionless non-Newtonian fluid mechanics – Dimensional Analysis
9. Revisiting Newtonian and Non-Newtonian Fluid Mechanics Using Computer Algebra – Revisiting Newtonian and Non-Newtonian Fluid Mechanics Using Computer Algebra.
10. Non-Newtonian Fluids: Interesting Thing of the Day – At Interesting Thing of the DaySome liquids have the curious property of behaving like solids when stress is applied. Walking across a vat full of cornstarch and water is just the beginning.
11. Research in Non-Newtonian Fluid Dynamics – Research Group at MIT
12. Non-Newtonian fluid – Discussion and Encyclopedia Article – Definition of Non-Newtonian fluid in an online ecyclopedia or dictionary, and discussion about Non-Newtonian fluid.
13. What is a Non-Newtonian Fluid? – Brief and Straightforward Guide: What is a Non-Newtonian Fluid?
14. Discovering fibres: Non-Newtonian Fluids – At Discovering fibres
15. Non-Newtonian fluid Summary – Non-Newtonian fluid. Non-Newtonian fluid summary with 2 pages of encyclopedia entries, research information, and more.

Although the concept of viscosity is commonly used to characterize a material, it can be inadequate to describe the mechanical behavior of a substance, particularly non-Newtonian fluids. They are best studied through several other rheological properties which relate the relations between the stress and strain rate tensors under many different flow conditions, such as oscillatory shear, or extensional flow which are measured using different devices or rheometers. The properties are better studied using tensor-valued constitutive equations, which are common in the field of continuum mechanics.

Gate Chemical Engineering Question Papers – Year 2009 – Part 03

Posted by admin on under GATE Exam | Be the First to Comment

1. The inverse Laplace transform of is

1. e-t/2 – e-t (B) 2e-t/2 – e-t

1. e-t – 2e-t/2 (D) e-t – e-t/2

1. The characteristic equation of a closed loop system using a proportional controller with gain Kc is

12 s3 + 19 s2 + 8 s + 1 + Kc = 0

At the onset of instability, the value of Kc is

1. 35/3 (B) 10 (C) 25/3 (D) 20/3

1. The block diagram for a control system is shown below :

For a unit step change in the set point, R(s), the steady state offset in the output Y(s) is

(A) 0.2 (B) 0.3 (C) 0.4 (D) 0.5

1. For a tank of cross-sectional area 100 cm2 and inlet flow rate (Qi in cm3/s), the outlet flow rate (Qo in cm3/s) is related to the liquid height (H in cm) as Qo = 3 ? H (see figure below).

Then the transfer function (overbar indicates deviation variables) of the process around the steady-state point, Qi,s = 18 cm3/s and Hs = 36 cm, is

(A) (B)

(C) (D)

1. A column costs Rs. 5.0 lakhs and has a useful life of 10 years. Using the double declining balance depreciation method, the book value of the unit at the end of five years (in lakhs of Rs.) is

(A) 1.21 (B) 1.31 (C) 1.64 (D) 2.05

1. An equi-molar mixture of four hydrocarbons (1, 2, 3, 4) is to be separated into high purity individual components using a sequence of simple distillation columns (one overhead and one bottom stream). Four possible schemes are shown below.

Scheme R Scheme S

Using the Ki (+ yi*/xi) values given above, the optimal scheme is

(A) P (B) Q (C) R (D) S

1. Match the equipment in Group I to the internals in Group II.

GROUP I GROUP II

1. Centrifugal pump 1. Baffle
2. Distillation column 2. Impeller
3. Heat exchanger 3. Tray

1. Volute

(A) P-2, Q-1, R-4 (B) P-2, Q-4, R-3

(C) P-1, Q-3, R-4 (D) P-4, Q-3, R-1

1. Match the product in Group I with the name of the process in Group II.

1 GROUP I GROUP II

2 P. Sodium carbonate 1. Haber

3 Q. Ammonia 2. Solvay

4 R. Sulphuric acid 3. Fischer-Tropsch

1. Contact

(A) P-2, Q-1, R-4 (B) P-4, Q-1, R-2

(C) P-3, Q-4, R-2 (D) P-2, Q-1, R-3

1. Match the product in Group I to the raw material in Group II.

1 GROUP I GROUP II

2 P. Ethylene 1. Natural gas

3 Q. Methanol 2. Synthesis gas

4 R. Phthalic anhydride 3. Naphtha

1. Naphthalene

(A) P-1, Q-2, R-3 (B) P-2, Q-1, R-4

(C) P-3, Q-1, R-4 (D) P-3, Q-2, R-4

1. Match the unit process in Group I with the industry in Group II GROUP I GROUP II

1. Steam cracking 1. Petroleum refining
2. Hydrocracking 2. Petrochemicals
3. Condensation 3. Polymers

4 Soaps and Detergents

(A) P-1, Q-2, R-3 (B) P-2, Q-3, R-3

(C) P-1, Q-2, R-4 (D) P-2, Q-1, R-3

Common Data Questions

Common Data for Questions 51 and 52 :

An ideal gas with molar heat capacity (where R = 8.314 J/mol.K) is compressed adiabatically from 1 bar and 300 K to pressure P2 in a closed system. The final temperature after compression is 600 K and the mechanical efficiency of compression is 50%.

1. The work required for compression (in kJ/mol) is

(A) 3.74 (B) 6.24 (C) 7.48 (D) 12.48

1. The final pressure P2 (in bar) is

1. 23/4 (B) 25/4 (C) 23/2 (D) 25/2

Common Data for Questions 53 and 54 :

A slab of thickness L with one side (x = 0) insulated and the other side (x = L) maintained at a constant temperature T0is shown below.

A uniformly distributed internal heat source produces heat in the slab at the rate of S W/m3. Assume the heat conduction to be steady and 1-D along the x-direction.

1. The maximum temperature in the slab occurs at x equal to

1. 0 (B) L/4 (C) L/2 (D) L

1. The heat flux at x = L is

1. 0 (B) S L/4 (C) S L/2 (D) S L

Common Data for Questions 53 and 54 :

A flash distillation drum (see figure below) is used to separate a methanol-water mixture. The mole fraction of methanol in the feed is 0.5, and the feed flow rate is 1000 kmol/hr. The feed is preheated in a heater with heat duty Qh and is subsequently flashed in the drum. The flash drum can be assumed to be an equilibrium stage, operating adiabatically. The equilibrium relation between the mole fractions of methanol in the vapor and liquid phases is y* = 4 x. The ratio of distillate to feed flow rate is 0.5.

1. The mole fraction of methanol in the distillate is

(A) 0.2 (B) 0.7 (C) 0.8 (D) 0.9

1. If the enthalpy of the distillate with reference to the feed is 3000 kJ/kmol, and the enthalpy of the bottoms with reference to the feed is –1000 kJ/kmol, the heat duty of the preheater (Qh in kJ/hr) is

1. –2×106 (B) –1×106 (C) 1×106 (D) 2×106

Linked Answer Questions :

Statement for Linked Answer Question 57 and 58 :

A free jet of water is emerging from a nozzle (diameter 75 mm) attached to a pipe (diameter 225 mm) as shown below.

The velocity of water at point A is 18 m/s. Neglect friction in the pipe and nozzle. Use g = 9.81 m/s2 and density of water = 1000 kg/m3.

1. The velocity of water at the tip of the nozzle (in m/s) is

(A) 13.4 (B) 18.0 (C) 23.2 (D) 27.1

1. The gauge pressure (in kPa) at point B is

(A) 80.0 (B) 100.0 (C) 239.3 (D) 367.6

Statement for Linked Answer Questions 59 and 60 :

The liquid-phase reaction AàB + C is conducted isothermally at 50°C in a continuous stirred tank reactor (CSTR). The inlet concentration of A is 8.0 gmol/liter. At a space time of 5 minutes, the concentration of A at the exit of CSTR is 4.0 gmol/liter. The kinetics of the reaction is

A plug flow reactor of the same volume is added in series after the existing CSTR.

1. The rate constant (k) for this reaction at 50°C is

(A) 0.2 (B) 0.2

(C) 0.4 (D) 0.4

1. The concentration of A (in gmol/liter) at the exit of the plug flow reactor is

(A) 0.5 (B) 1.0 (C) 2.0 (D) 2.5

Gate Chemical Engineering Question Papers – Year 2009 – Part 02

Posted by admin on under GATE Exam | Be the First to Comment

1. 21 to Q. 60 carry two marks each.

1. The value of the limit –is

(A) –? (B) 0 (C) 1 (D) ?

1. The general solution of the differential equation –

= 0,

with C1 and C2 as constants of integration, is

1. C1 e-3x + C2 e-2x (B) C1 e3x + C2 e-2x

1. C1 e3x + C2 e2x (D) C1 e-3x + C2 e2x

1. Using the residue theorem, the value of the integral (counter clockwise)

around a circle with center at z = 0 and radius = 8 (where z is a complex number and i = ), is

1. – 20? i (B) – 40? (C) – 40? i (D) 40? i

1. Consider the integral,

over the surface of a sphere of radius = 3 with center at the origin and surface unit normal n pointing away from the origin. Using the Gauss divergence theorem, the value of this integral is

(A) – 180? (B) 0 (C) 90? (D) 180?

1. Using the trapezoidal rule and 4 equal intervals (n = 4), the calculated value of the integral (rounded to the first place of decimal)

1 is

(A) 1.7 (B) 1.9 (C) 2.0 (D) 2.1

1. The eigenvalues of matrix are 5 and –1. Then the eigenvalues of –2A + 3I (I is a 2 x 2 identity matrix) are

1. –7 and 5 (B) 7 and –5 (C) and (D) and

1. A fair die is rolled. Let R denote the event of obtaining a number less than or equal to 5 and S denote the event of obtaining an odd number. Then which ONE of the following about the probability (P) is TRUE ?

1. P(R/S) = 1 (B) P(R/S) = 0 (C) P(S/R) = 1 (D) P(S/R) = 0

1. Pure water (stream W) is to be obtained from a feed containing 5 wt % salt using a desalination unit as shown below:

Recycle (R)
Feed (F) Mixed feed Effluent

5 wt % salt 10 wt % salt Desalination

unit

1. Pure water (W)
2. 0 % salt

If the overall recovery of pure water (through stream W) is 0.75 kg/kg feed, then the recycle ratio (R/F is

(A) 0.25 (B) 0.5 (C) 0.75 (D) 1.0

1. For a binary mixture at constant temperature and pressure, which ONE of the following relations between activity coefficient (?i) and mole fraction (xi) is thermodynamically consistent ?

1. ln ?1 = –1 + 2 x1 , ln ?2 =
2. ln ?1 = –1 + 2 x1 , ln ?2 =
3. ln ?1 = –1 + 2 x1 , ln ?2 =
4. ln ?1 = –1 + 2 x1 , ln ?2 =

1. Two identical reservoirs, open at the top, are drained through pipes attached to the bottom of the tanks as shown below. The two drain pipes are of the same length, but of different diameters (D1 > D2).

Assuming the flow to be steady and laminar in both drain pipes, if the volumetric flow rate in the larger pipe is 16 times of that in the smaller pipe, the ratio D1/D2 is

(A) 2 (B) 4 (C) 8 (D) 16

1. For an incompressible flow, the x- and y- components of the velocity vector are

?x = 2 (x + y); ?y = 3 (y + z);

where x, y, z are in metres and velocities are in m/s. Then the z-component of the velocity vector (vz) of the flow for the boundary condition vz = 0 at z = 0 is

1. 5 z (B) –5 z (C) 2x + 3z (D) –2x–3z

1. The terminal settling velocity of a 6 mm diameter glass sphere (density: 2500 kg/m3) in a viscous Newtonian liquid (density: 1500 kg/m3) is 100 ?m/s. If the particle Reynolds number is small and the value of acceleration due to gravity is 9.81 m/s2, then the viscosity of the liquid (in Pa.s) is

(A) 100 (B) 196.2 (C) 245.3 (D) 490.5

1. A well-insulted hemispherical furnace (radius = 1 m) is shown below:

The self-view factor of radiation for the curved surface 2 is

1. 1/4 (B) 1/2 (C) 2/3 (D) 3/4

1. A double-pipe heat exchanger is to be designed to heat 4 kg/s of a cold feed from 20 to 40°C using a hot stream available at 160°C and a flow rate of 1 kg/s. The two streams have equal specific heat capacities and the overall heat transfer coefficient of the heat exchanger is 640 W/m2.K. Then the ratio of the heat transfer areas require for the co-current to counter-current modes of operations is

(A) 0.73 (B) 0.92 (C) 1.085 (D) 1.25

1. For the composite wall shown below (case 1), the steady state interface temperature is 180°C. If the thickness of layer P is doubled (Case 2), then the rate of heat transfer (assuming 1-D conduction) is reduction by

(A) 20% (B) 40% (C) 50% (D) 70%

1. Species A is diffusing at steady state from the surface of a sphere (radius = 1 cm) into a stagnant fluid. If the diffusive flux at a distance r = 3 cm from the center of the sphere is 27 mol/cm2.s, the diffusive flux (in mol/cm2.s) at a distance r = 9 cm is

(A) 1 (B) 3 (C) 9 (D) 27

1. The feed to a binary distillation column has 40 mol % vapor and 60 mol % liquid. Then, the slope of the q-line in the McCabe-Thiele plot is

(A) –1.5 (B) –0.6 (C) 0.6 (D) 1.5

1. The equilibrium moisture curve for a solid is shown below :

The total moisture content of the solid is X and it is exposed to air of relative humidity H. In the table below, Group Ilists the types of moisture, and Group II represents the region in the graph above

Group I Group II

1. Equilibrium moisture 1
2. Bound moisture 2
3. Unbound moisture 3
4. Free moisture 4

Which ONE of the following is the correct match ?

(A) P-1, Q-2, R-3, S-4 (B) P-1, Q-3, R-4, S-2

(C) P-1, Q-4, R-2, S-3 (D) P-1, Q-2, R-4, S-3

1. The liquid-phase reaction A à B is conducted in an adiabatic plug flow reactor.

Data :

Inlet concentration of A = 4.0 k.mol/m3

Density of reaction moisture (independent of temperature = 1200 kg/m3

Average heat capacity of feed stream (independent of temperature) = 2000 J/kg.k

Heat of reaction (independent of temperature) = –120 kJ/mol of A reacting

If the maximum allowable temperature in the reactor is 800 K, then the feed temperature (in K) should not exceed.

(A) 400 (B) 500 (C) 600 (D) 700

1. An isothermal pulse test is conducted on a reactor and the variation of the outlet tracer concentration with time is shown below :

The mean residence time of the fluid in the reactor (in minutes) is

(A) 5.0 (B) 7.5 (C) 10.0 (D) 15.0

Gate Chemical Engineering Question Papers – Year 2009 – Part 01

Posted by admin on under GATE Exam | Be the First to Comment

CHEMICAL ENGINEERING – Gate Chemical Engineering Question Papers – Year 2009

• There are a total of 60 questions carrying 100 marks. Questions 1 through 20 are 1-mark questions; questions 21 through 60 are 2-mark questions.
• Questions 51 through 56 (3 pairs) are common data questions and questions pairs (57, 58) and (59, 60) are linked answer questions. The answer to the second question of the above 2 pairs depends on the answer to the first question of the pair. It the first question in the linked pair is wrongly answered or is un-attempted, then the answer to the second question in the pair will not be evaluated.
• Questions not attempted will carry zero marks.
• Wrong answers will carry NEGATIVE marks. For Q.1 to Q.20, 1/3 mark will be deducted for each wrong answer. For Q.21 to Q.56, 2/3 marks will be deducted for each wrong answer. The questions pairs (Q.57, Q.58) and (Q.59, Q.60) are questions with linked answers. There will be negative marks only for wrong answer to the first question of the linked answer question pair i.e. for Q.57 and Q.59, 2/3 mark will be deduced for each wrong answer. There is no negative marking for Q.58 and Q.60.

Q.1 – Q.20 carry one mark each.

1. The direction of largest increase of the function xy3 – x2 at the point (1,1) is

(A) (B) (C) (D)

1. The modulus of the complex number is

(A) (B) (C) 1 (D)

1. The system of linear equations Ax = 0, where A is an n ´ n matrix, has a non-trivial solution ONLY if

1. rank of A > n (B) rank of A = n

1. rank of A < n. (D) A is an identity matrix

1. A dehumidifier (shown below) is used to completely remove water vapor from air.

Which ONE of the following statements is TRUE ?

1. Water is the ONLY tie component
2. Air is the ONLY tie component,
3. BOTH water and air are the components
4. There are NO tie components

1. Dehydrogenation of ethane, C2H6 (g) àC2H4 (g) + H2 (g), is carried out in a continuous stirred tank reactor (CSTR). The feed is pure ethane. If the reactor exit stream contains unconverted ethane along with the products, then the number of degrees of freedom for the CSTR is

(A) 1, (B) 2, (C) 3, (D) 4

1. An ideal gas at temperature T1 and pressure P1 is compressed isothermally to pressure P2 (> P1) in a closed system. Which ONE of the following is TRUE for internal energy (U) and Gibbs free energy (G) of the gas at the two states ?

1. U1 = U2, G1 > G2 (B) U1 = U2, G1 < G2

1. U1 > U2, G1 = G2 (D) U1 < U2, G1 = G2

1. Under fully turbulent flow conditions, the frictional pressure drop across a packed bed varies with the superficial velocity (V) of the fluid as

1. V -1 (B) V (C) V 3/2 (D) V 2

1. For a mixing tank operating in the laminar regime, the power number varies with the Reynolds number (Re) as

1. Re –1/2 (B) Re 1/2 (C) Re (D) Re -1

1. During the transient convective cooling of a solid object, Biot numberà0 indicates.

1. Uniform temperature throughout the object
2. Negligible convection at the surface of the object
3. Significant thermal resistance within the object
4. Significant temperature gradient within the object

1. The Prandtl number of a fluid is the ratio of

1. Thermal diffusivity to momentum diffusivity
2. Momentum diffusivity to thermal diffusivity
3. Conductive resistance to convective resistance
4. Thermal diffusivity to kinematic diffusivity

1. According to the penetration theory of mass transfer, the mass transfer coefficient (k) varies with diffusion coefficient (D) of the diffusing species as

1. D (B) D -1/2 (C) D 1/2 (D) D 3/2

1. The ratio of the liquid to gas flow rate in a counter-current gas absorption column is increased at otherwise identical conditions. Which ONE of the following statements is TRUE ?

1. The operating line shifts towards the equilibrium curve
2. The operating line shifts away from the equilibrium curve
3. The concentration of the absorbed species increases in the exit liquid stream
4. The operating line dies not shift.

1. For a homogeneous reaction system, where

Cj is the concentration of j at time t

Nj is the number of moles of j at time t

V is the reaction volume at time t

t is the reaction time.

The rate of reaction for species j is defined as

(A) (B) (C) (D)

1. The half-life of a first order liquid phase reaction is 30 seconds. Then the rate constant, in min-1, is

(A) 0.0231 (B) 0.602 (C) 1.386 (D) 2.0

1. For a solid-catalyzed reaction, the Thiele modulus is proportional to
2. Which ONE of the following sensors is used for the measurement of temperature in a combustion process (T > 1800°C) ?

1. Type J thermocouple, (B) Thermistor

1. Resistance temperature detector, (D) Pyrometer.

1. The roots of the characteristic equation of an under damped second order system are

1. Real, negative and equal, (B) Real, negative and unequal,

1. Real, positive and unequal, (D) Complex conjugates.

1. The total fixed cost of a chemical plant is Rs. 10.0 lakhs; the internal rate of return is 15% and the annual operating cost is Rs. 2.0 lakhs. The annualized cost of the plant (in lakhs of Rs.) is

(A) 1.8 (B) 2.6 (C) 3.5 (D) 4.3

1. In petroleum refining operations, the process used for converting paraffins and naphthenes to aromatics is

1. Catalytic reforming (B) Catalytic cracking

1. Hydrocarcking, (D) Alkylation.

1. The active component of catalysts used in steam reforming of methane to produce synthesis gas is

1. Nickel (B) Iron (C) Platinum (D) Palladium

Navier Stokes Equation In Cylindrical Coordinates

Posted by admin on October 30, 2009 under Fluid Mechanics | Be the First to Comment

The Navier–Stokes equations, named after Claude-Louis Navier and George Gabriel Stokes, describe the motion of fluid substances, that is substances which can flow. These equations arise from applying Newton’s second law to fluid motion, together with the assumption that the fluid stress is the sum of a diffusing viscous term (proportional to the gradient of velocity), plus a pressure term.

They are exceptionally useful because they describe the physics of many things of academic and economic interest. They may be used to model the weather, ocean currents, water flow in a pipe, the air’s flow around a wing, and motion of stars inside a galaxy. The Navier–Stokes equations in their full and simplified forms help with the design of aircraft and cars, the study of blood flow, the design of power stations, the analysis of pollution, and many other things. Coupled with Maxwell’s equations they can be used to model and study magnetohydrodynamics.

The Navier–Stokes equations are also of great interest in a purely mathematical sense. Somewhat surprisingly, given their wide range of practical uses, mathematicians have not yet proven that in three dimensions solutions always exist (existence), or that if they do exist, then they do not contain any singularity (or infinity or discontinuity) (smoothness). These are called the Navier–Stokes existence and smoothness problems.

Reference : Navier Stokes Equation at Wikipedia

Here are some websites on Navier Stokes Equation in Cylindrical Coordinates.

1. WikiAnswers – What is the derivation of Navier-Stokes equation in cylindrical coordinates for incompressible flow – Numerical Analysis and Simulation question: What is the derivation of Navier-Stokes equation in cylindrical coordinates for incompressible flow?
2. Conversion from Cartesian to Cylindrical Coordinates – Conversion from Cartesian to Cylindrical Coordinates Calculus
3. A formulation of Navier Stokes problem in cylindrical coordinates applied to the 3D entry jet in a duct – ScienceDirect – Journal of Computational Physics
4. Fluid Dynamics and the Navier-Stokes Equations – Fluid Dynamics and the Navier-Stokes Equations
5. Navier Stokes Equation – Navier Stokes Equation
6. Navier-Stokes equations – Facts, Discussion Forum, and Encyclopedia Article
7. Navier-Stokes equations – Example Problems – Solved Problems on Navier Stokes Equation Cylindrical Coordinates

The Navier-Stokes equations dictate not position but rather velocity. A solution of the Navier-Stokes equations is called a velocity field or flow field, which is a description of the velocity of the fluid at a given point in space and time. Once the velocity field is solved for, other quantities of interest (such as flow rate or drag force) may be found.

This is different from what one normally sees in classical mechanics, where solutions are typically trajectories of position of a particle or deflection of a continuum. Studying velocity instead of position makes more sense for a fluid, however for visualization purposes one can compute various trajectories.

Boiling Point Of Water Calculator

Posted by admin on under Chemical Process Calculation | Be the First to Comment

What is Boiling Point Of Water?

The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. A liquid in a vacuum environment has a lower boiling point than when the liquid is at atmospheric pressure. A liquid in a high pressure environment has a higher boiling point than when the liquid is at atmospheric pressure. In other words, the boiling point of liquids varies with and depends upon the surrounding environmental pressure.

Different liquids boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, 1 atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and lift the liquid to form bubbles inside the bulk of the liquid. The standard boiling point is now (as of 1982) defined by IUPAC as the temperature at which boiling occurs under a pressure of 1 bar.

The heat of vaporization is the amount of energy required to convert or vaporize a saturated liquid (i.e., a liquid at its boiling point) into a vapor.

Reference – Boiling Point of Water at Wikipedia

Here are some links related to Boiling Point Of Water Calculator.

1. Water Altitude Boiling Point Calculator – Water Altitude Boiling Point Calculator
2. Boiling Point Calculator for Ethanol and Water – Simple calculator evaluating boiling point of ethanol under reduced pressure.
3. Boiling Point Calculator – Simple calculator evaluating boiling point under reduced pressure.
4. Forum Question: Boiling point of water versus pressure – Forum Question: Boiling point of water versus pressure
5. Boling Point Calculator – greeneggers.net – The rebirth of the ancient oriental Kamado cooker.
6. Boiling Point Computation – Boiling Point Computation
7. What is the boiling point of water at 11,000 feet? – Yahoo! Answers – Is there a formula to adjust the boiling point at …
8. At what tempeture does water boil – at Answerbag.com

Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation. Evaporation is a surface phenomenon in which molecules located near the vapor/liquid surface escape into the vapor phase. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid.

Rankine Cycle Thermodynamics

Posted by admin on October 3, 2009 under Thermodynamics | Read the First Comment

The Rankine cycle is a thermodynamic cycle which converts heat into work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid. This cycle generates about 80% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants. It is named after William John Macquorn Rankine, a Scottish polymath.

A Rankine cycle describes a model of the operation of steam heat engines most commonly found in power generation plants. Common heat sources for power plants using the Rankine cycle are the combustion of coal, natural gas, oil, and nuclear fission.

The Rankine cycle is sometimes referred to as a practical Carnot cycle as, when an efficient turbine is used, the TS diagram will begin to resemble the Carnot cycle. The main difference is that a pump is used to pressurize liquid instead of gas. This requires about 1/100th (1%) as much energy[citation needed ] than that compressing a gas in a compressor (as in the Carnot cycle ).

Thermal Efficiency Rankine Cycle

1. Rankine cycle – Wikipedia, the free encyclopedia – at Wikipedia
2. Rankine Cycle – Rankine Cycle
3. 8.5 Rankine Power Cycles – 8.5 Rankine Power Cycles
4. Thermodynamics eBook: Rankine Cycle – eBook on Thermodynamics
5. Thermodynamics: Facts, Discussion Forum, and Encyclopedia Article – Discussion Forum
6. Rankine Cycle Power Vapor Turbine Pressure Heat Fluid Liquid – Rankine Cycle Power Vapor Turbine Pressure Heat Fluid Liquid Economy.

In physics, thermodynamics is the study of the conversion of heat energy into different forms of energy ; different energy conversions into heat energy; and its relation to macroscopic variables such as temperature, pressure, and volume cycle which converts heat into work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid. This cycle generates about 80% of all electric power used throughout the world., including virtually all solar thermal, biomass.