Skip to main content

Science – Society – Technology

Table 8 Comparison of real observations and conditions with calculation results of scenarios 1–4. The critical flow velocity \({U_{critical = min.}}\) and the washout flow velocity \({U_{washout = max.}}\) were calculated by Eq. 12 considering also the parameter ranges. The ripple height and ripple length were calculated by Eqs. 4 and 5 considering also the parameter ranges. In the lower part of the table, ripple length and height predictions by the simple Eqs. 13 are indicated for comparison. Empty fields: unknown parameters, n.v. = equations not valid for the given input parameters (out of calibration)

From: Rippled scales in a geothermal facility in the Bavarian Molasse Basin: a key to understand the calcite scaling process

 

Observed ripple geometries

Observed conditions during production

Observed conditions during maintenance

Scenario 1 (production \(22\, \mu \hbox {m}\) calcite)

Scenario 2 (production \(150\, \mu \hbox {m}\) flocc. calcite)

Scenario 3 (maintenance \(22 \, \mu \hbox {m}\) calcite)

Scenario 4 (maintenance \(92 \, \mu \hbox {m}\) coated oil)

T, \(^\circ \hbox {C}\)

 

139

20

139

139

20

20

\({\dot{V}}\)

 

110

\(5\, \pm \,2\)

110

110

\(5\, \pm \,2\)

\(5\, \pm \,2\)

\(\nu\), \(10^{-7}\cdot \, {\hbox {m}}^2/\hbox {s}\)

 

2.19

9.81

2.19

2.19

9.81

9.81

\(\rho _p\), \({\hbox {kg/m}}^3\)

 

\(2710\, \pm \,0.14\)

\(2710\, \pm \,0.14\)

\(2710\, \pm \,0.14\)

\(2710\, \pm \,0.14\)

\(2710\, \pm \,0.14\)

\(1073\,\pm \,28\)

\(\rho _l\), \({\hbox {kg/m}}^3\)

 

927

 

927

927

\(1020\, \pm \,10\)

\(1020\, \pm \,10\)

\({\hbox {d}}_{50}\), \(\hbox {m} \cdot 10^{-6}\)

22 (Q1: 18, Q3: 28)

  

22 (Q1: 18, Q3: 28)

150

22 (Q1: 18, Q3: 28)

92 (Q1: 71, Q3: 117)

D*

   

1.35 – 2.00

11.00

0.44 – 0.73

0.38 - 1.4

\(\Theta _c\)

   

0.09 - 12

0.03

0.16 - 0.20

0.12 - 0.21

\({U_{critical = min.}}\), m/s

 

1.2

0

0.18

0.22

0.21

0.04

\({U_{washout = max.}}\), m/s

 

2.2

0.08

0.52

0.33

0.58

0.23

\(\eta _{max}\), \(\hbox {m} \cdot 10^{-3}\)

1.2

  

3.1 - 3.9

8

n.v.

n.v.

\(\lambda _{max}\), \(\hbox {m} \cdot 10^{-3}\)

9.7

  

31 - 33

83

n.v.

n.v.

\(\eta _{max-flem.}\), \(\hbox {m} \cdot 10^{-3}\)

1.2

  

1.2 - 1.9

10

1.2 - 1.9

4.8 - 7.9

\(\lambda _{max-colem.}\), \(\hbox {m} \cdot 10^{-3}\)

9.7

  

8.6 - 12.0

42

8.6 - 12.0

24 - 35

\(\lambda _{max-yalin}\), \(\hbox {m} \cdot 10^{-3}\)

9.7

  

18 - 28

150

18 - 28

71 - 117