MIN 470 Final Exam April 16, 2018

Question 1.

(20 marks) Silica is one of the listed designated substances in Ontario legislation. What is the

significance of the term "designated substance"?

What are the four "routes of entry" categories for physical contaminants and the human body?

C) Describe the "Swiss cheese" model as it relates to occupational health management.

d) What was your topic for the occupational health independent study project? What was the most important management strategy for dealing with this contaminant in the workplace?

Question 2. (20 marks) A company has developed a novel ducting material with a K-factor of 0.0018 Ns2m4. An old product is made from canvas material with a 1.055 m diameter round cross section. The new manufactured product is made with the new material with a square profile. Specify the dimensions of the new duct so that the system frictional resistance is the same per unit length.

Question 3. (15 marks) Describe the principle of selecting a good ventilation measurement location that is illustrated in this figure. Why is this important?

Question 4. (30 marks) A fan selection exercise is being done for a deep mine where the operating conditions are predicted to be 27 °C, 80% relative humidity, and 130 kPa atmospheric pressure.

Calculate the expected air density.

The following chart is for standard density of 1.200 kg/M3. Calculate a new performance chart (flow, total pressure, power) for the density calculated in subsection 'a".

Q [m3/s] Total Pressure [Pa] Power [kW]

19.36 2526 69.35

23.61 2240 74.57

28.33 1692 74.57

33.05 647 66.37

Question 5. Draw only one or two lines to show how to connect the pitot-static tube to the manometer ports in order to directly measure the specified property. Unfortunately the manometer used can only measure positive values so if your tubes are backwards then it will not work. Draw your solution here on this page, but also write your name on the page. (18 marks)

a) Total Pressure b) Velocity Pressure

c) Static Pressure d) Fan Total Pressure

+o +o e) Fan Total Pressure at Exit f) Fan Total Pressure at Entrance

Question 6. (30 marks) Consider the following fan and duct arrangement. The velocity pressures and pressure losses (above duct) have been measured and provide in pascals.

10 290 50 200 180 20 600 40

Pv=50

A BC DE F H I Calculate the following:

Gauge static pressure and gauge total pressure at each labeled location Fan total pressure and static pressure Shock loss coefficient on entrance Evasee efficiency on exit

Question 7.

(30 marks)

Using the attached psychrometric chart (101.325 kPa), solve the following graphically:

Locate Point A at 10°C dry-bulb, enthalpy of 20 kJ/kg dry air

Locate Point B at 35 °C dry-bulb, 30 % relative humidity

C) Locate Point C, which is an adiabatic mixture of A and B at 25 °C dry-bulb.

If the flow rate of A is 20 m/s, what is the flow rate of B to create the mixture of C?

Complete the following table of psychrometric state-point properties on this page:

Dry Bulb [°C]

R. H. [%]

Wet Bulb [°Ci

Humidity Ratio [kg/kg]

A.S.V. [m3/kg]

Enthalpy [kJ/kg]

Point A

Point B

Point C

Note: write your name on this page.

Question 8.

(30 marks)

Consider the following network with resistance values specified in Ns2/m8 for each segment:

Ri = 0.20 R2 = 0.20 R3 = 0.20

R4 = 0.30 I, "IR6 = 05

R7 = 0.10

Simplify the network to a single resistance. Calculate the flow and pressure drop in each segment if the flow in the first segment is Q1 =

100 m3/s.

PV = riRT Tri - Md. = 28.966 kg/kmol

Al M = 18.015268 kg/kmol

Rspecifc P R = 8.3144598 kJ/(Kkmol)

Al R8pecif T Rd. = 0.287042 kJ/(kgK)

R = 0.461523 kJ/(kgK)

17.27-T P = 0.6105C 237.3+T P., Pws100

RH 5 r 0.62194

Pbaro -

PbaroPn) p=pd(L .(1+r) P=pgh Pda

RdaT

P0 + puü + pgho + Pfan P1 + pU + pg/it + Pfrjct ion + Ps/ jock

P,0 + P,0 + pgho + an = PS11 + P,1 + pgh1 + Pfriction + Pshock

D = puD

Re = p 2

= fd L it

1,325 KCLu2 p P1 =P5 +P e/D 5 + .74

09 2 -- (ln(-

3.7 )) Pfriction

A 1.2

= 1 pit 2 P = RQ2 f =

KCL R

p

A3 1.2

Px =xPc P=Gd .p?i2 X0 = G4

Xp

2A2Leq

0.6XA W=QxP KG

AetnaiStatiePressureRe gain -

VVTOU ,pu1

= •100% TIC

TheoretiealStaticPressureRegairi 11—

V/input

= (1 ii)AP Pe.regain = TIAPv

Network Simplification

1

Rtotai = R1 +R2 + + R Rtotai = + + +

Psychrometry & Thermodynamics

1 RdaT Vda =

Pda Pbaro - Pw

h = 1.005 tdb + r [2501 + 1.884 tdb]

S = 1.005 tdb + r [2501-4.262 twb + 1.884 tdb]

cop wlnput

C0PCarnot tevaporator

tcondenser - tevaporator

Fan Affinity Laws

Q2 N2 ( \3

xL Q1 N 1D1 ) Kp2

H2

NI D1'X(D2

) p1 Kp2

=1 XL?XPL P LN1) D1 ) p1 Kp2

Hardy Cross

I (RQa Qa - Pf an) -

(2RQa + S1)

Capital Recovery Factor

(A/P,i,n) = i(1+i)

(1 + On - 1

Atkinson Friction Factors

Airway K [Ns2/m4]

Ventilation piping (steel I fibreglass) 0.003

Concrete lined empty shaft 0.004

Straight rock tunnel 0.01

Concrete lined shaft with streamlined buntons 0.025

Concrete lined shaft with R.S.J. buntons 0.05

Heavily timbered rectangular shaft 0.08

Raise bored hole 0.0024

Duct Material K [Ns2/m4] K [1010 lb- min 2 I ft4]

Galvanized / fiberglass, new 0.0028 15

Galvanized / fiberglass, used 0.0037 20

Canvas / plastic, new 0.0037 20

Canvas I plastic, used 0.0046 25

Spiral-Canvas, new 0.0111 60

Spiral-Canvas, used 0.0136 73.3

k- -R2 j.,

35

.45

: ':

15

' .8O

-21

Y..y 1.5 2 3 4 6 8 10 15 20 30 40 61

L/Rt - LENGTH TO INLET RADIUS RATIO

40

30

20

15

10

8

6

2.5

2.0

1.8

1.6

1.4

1.3

1.2