IST / DEQ

Master in Chemical Engineering

Master in Biological Engineering

MEGE

Fenómenos de Transferência I

2016-2017 - 1st semester
Test 1 / 05.11.2016 / 09:00 h / Duration1:45 h

Docentes: Alda Simões; M. Teresa Reis; João Fareleira

nr: / Name:
Course:

Parte A – Multiplechoicequestions

In the following questions only one of the answer is right. Mark your choice clearly. The use of calculators or draft paperis not allowed until you deliver this sheet.

For each right answer: 0,50 vFor each wrong answer: -0,125 v

  1. The kinematic viscosity of water at 20°C is approximately:
  2. 1 cm2 s-1
  3. 1 centistoke
  4. 1 poise
  5. 1 centipoise
  6. 1 g cm-3
  1. “Apparentviscosity” means:
  2. Kinematicviscosity.
  3. The viscosity of a fluidat rest.
  4. The ratio between the applied force and the velocity gradient.
  5. The slope of the tangent to the curve of rheological behavior (stress – deformation) under the working conditions.
  6. The viscosity when the velocity increases with time.
  1. Consider Casson’s equation, . The constantkCwill correctly be expressed in:
  2. g1/2s-1/2cm-1/2
  3. Pa1/2 s
  4. Pa s-1
  5. kg1/2 m-1/2s-3/2
  6. kg m-2s-1/2
  1. A fluid flows without friction in a tube, according to the scheme. Which of the sections have highest pressure and velocity, respectively?
  2. Aand D
  3. Band B
  4. Cand B
  5. Dand C
  6. Cand C
  1. Which of the following conditions are required for the validity of Bernoulli equation? I. Steady state II. Along a streamline III. Viscous flow IV. Incompressibleflow.
  2. I, II, III e IV
  3. I e II only
  4. I, II e III only
  5. I, II e IV only
  6. None of the above answers.
  1. In a riot the police uses water jets to fight themob. If one person uses a flat shield placed vertically and the water hits the shield horizontally and is totally dispersed in other directions, according to the scheme, what is the value closest to the resulting force on the shield, for a velocity of40 m/sand a jet with 4 cm diameter (expressed in Newton)?
  2. 16π
  3. 65π
  4. 160 π
  5. 640 π
  6. 1280π

Instituto Superior Técnico

Departamento de Engenharia Química

Fenómenos de Transferência I / TransportPhenomena I

MEB -Mestrado em Engenharia Biológica

MEQ - Mestrado em Engenharia Química

MEGE - Mestrado em Engenharia e Gestão da Energia

2016-2017 - 1º Semestre
1º Teste / 05.11.2016 / 09:00 h Duração 1:45 H

Docentes: Alda Simões; João Fareleira; Maria Teresa Reis

Part B

  1. (6,0) A cylindrical tank with 3.0 meters height of a liquid drains to the atmosphere through a tube with 1 inch internal diameter, located at the bottom of the tank. In the absence of friction, what is the tank diameter that results in a total discharge time of 120 minutes?
  1. (5,0) The velocity distribution for a newtonian liquid with thickness δ flowing down a wall in viscous flow is given by:

a)What is the velocity at the two interfaces?

b)What is the shear stress at the two interfaces?

c)If the liquid had a Bingham-typebehavior, what would the distribution be like? Describe qualitatively and justify by your own words.

  1. (6,0) Hexane (ρ= 660 kg m-3) flows without friction up the Venturitube in the scheme. The diameter of the tube is 25 cm in the wider section and 20 cm in the smaller section. Knowing that the manometric liquid is water and that the reading in the manometer is 30 cm, determine the volume flow rate. Assume plug-flow velocity distribution.

FT I / Test 1 a / 5 Nov 2016