Experiment 8

Calibration of the Laminar Flow element, the Rota meter and the Turbine Flow meter

Objectives:

To use the Laminar Flow element, the Rota meter and the Turbine Flow meter to

measure the rate of discharge.

To determine the coefficient of discharge Cd for both the Venturi Meter and the

Orifice Meter.

Apparatus:

Turbine

Flow meter

Rota meter

Laminar Flow

element

Procedure:

Turn on the air compressor

Open the air regulator valve

Take the readings

Repeat procedure for 4 different positions

Readings:

zero 1st 2nd 3rd 4th 5th

Ps (kPa) 850 790 680 565 600 630

P1 (kPa)

100 150 200 250 300

P2 (kPa)

15 22 30 42 54

P3 (kPa)

10 18 24 36 48

Rota meter 30 40 49 57 64

laminar flow (mm) 22 79 96 108 116 121

turbine rate 520 645 735 800 848

venturi Loss (cm H2O) 1.4 3.3 4.2 4.8 5.5 6.2

Diff (cm H2O) 1.5 9.8 15.5 20.7 25.8 31.8

orifice Loss (cm H2O) 1.6 9 14.8 19.8 24.5 29.3

Diff (cm H2O) 1.5 9.8 16.3 21.8 27.7 32.3

Time (sec)

11.7 9.5 7.8 6.3 4.9

Volume (m3)

0.015 0.015 0.015 0.015 0.015

Sample of calculation (5th point):

𝑄4 =∆v

𝑡=

0.15

4.9= 3.06122449 × 10−2 𝑚3/𝑠

𝜌 =𝑃4

𝑅𝑇=

48 × 103

287 × (273 + 31)= 0.5501558𝑘𝑔/𝑚3

�̇� = 𝑄 × 𝜌 = 3.06122449 × 10−2 × 0.5501558 = 1.68415 × 10−2𝑘𝑔/𝑠 Laminar Flow Element:

𝐶𝑑 =𝑚𝐿𝐹𝐸

𝐾 × ∆𝑃 × 𝜌=

1.68415 × 10−2

(11.6 × 10−3)(12.1 − 2.2)(0.5501558)= 0.266564

Rota meter:

𝜌𝑟 =(𝜌𝑠 + 𝜌𝑎𝑡𝑚) × 1000

287(273 + 𝑡)=

(0.5501558 + 1.013) × 1000

287(273 + 31)= 0.01791623𝑘𝑔/𝑚3

𝐶𝑑 =�̇�

2.14 ×𝑅

1000× √

𝜌𝑟

𝜌𝑠

=1.68415 × 10−2

2.14 ×64

1000× √0.01791623

0.5501558

= 0.650

Turbine Meter:

𝑄𝑡 = 0.14 × 𝑇𝑀𝐼 = 0.14 × 848 = 118.72 𝑙𝑖𝑡/𝑠𝑒𝑐

𝜌 =(𝜌𝑠 + 𝜌𝑎𝑡𝑚) × 1000

287(273 + 𝑡)=

(0.5501558 + 1.013) × 1000

287(273 + 31)= 0.01791623𝑘𝑔/𝑚3

𝐶𝑑 =�̇�

𝑄𝑡

1000× 𝜌

=1.68415 × 10−2

118.721000

× 0.01791623 × 60= 0.131965

Results: Q (m3/s) 0.012821 0.015789 0.019231 0.02381 0.030612

raw (kg/m3) 0.114616 0.206308 0.275078 0.412617 0.550156

m dot (kg/s) 0.001469 0.003258 0.00529 0.009824 0.016842

laminar flow element cd 0.193898 0.183941 0.19277 0.218356 0.266564

raw r 0.012924 0.013975 0.014763 0.01634 0.017916

TMI Qt 72.8 90.3 102.9 112 118.72

cd 0.026029 0.043022 0.058036 0.089471 0.131965

rota mater cd 0.068161 0.146214 0.21776 0.404724 0.681407

Graghs:

0

0.05

0.1

0.15

0.2

0.25

0.3

0 0.005 0.01 0.015 0.02

Cd

m dot

laminar flow element

Comments: - The three meters are used for measuring the flow

- Turbine meter is preferred since it allows us to take the electrical signal to

the computer and thus used in the automatic controls

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 0.005 0.01 0.015 0.02

Cd

m dot

TMI

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.005 0.01 0.015 0.02

Cd

m dot

rota mater