5.3 Setup of Case Studies
71
In order to extract the fluidic resistance R, additionally, the resistance M ii (Eq. 5.3)
of the input channel and periphery was measured. Therefore, the outputs Out1, Out2,
Out3, and Out4 were closed. Afterwards, the fluidic valves including the flow sensor
were connected one after another to the output Out5. Eventually, this allowed to
measure the overall resistance of R V , R tub , R valve , and R sens , i.e.
M ii = R V + R tub + R valve + R sens .
(5.3)
Having M i and M ii allowed to obtain the resistance of the meander (Eq. 5.4), i.e.
R = M i − M ii .
(5.4)
For measuring the resistances of the meander channels, water having a viscosity
of 1 mPa s was used. This water was driven by a pressure pump, which was
connected at input In. The pump applied increasing pressures ranging from 0 to
1000 mbar using a step width of 50 mbar. Similarly, the pressure was decreased
with the same step width. Each pressure value was fixed for 30 s and approximately
20 measurements were conducted in 1 s. This procedure was repeated for all four
meanders contained on the microfluidic device (i.e., only a single valve was open at
a time). Overall, this resulted for each of the considered fluidic resistances in a data
set containing the current time, the set pressure, the internal pressure, the resulting
volumetric flow rate, and the respective state of the fluidic valves.
For analyzing the obtained data set, a script allowed to split the data into blocks.
Here, a block contained the measurements for one dedicated pressure value (either
in the pressure increasing or decreasing phase) and one meander. Using such a
data block, the script allowed to determine the fluidic resistance by the quotient
between the pressure and the volumetric flow rate. Here, the median value of the
pressure/flow rate was used because this prevented that eventual spikes skew this
value in the measurements.
The results obtained by the different data blocks were afterwards further
aggregated: First, the median of the fluidic resistances was built separately for the
increasing and decreasing phase of the pressure for each meander. Overall, this
resulted in eight resistance values for the two phases and the four meanders on the
considered microfluidic device. Finally, again the median was built over these eight
values.
5.3.3 Setup for Realizing Dedicated Mixing Ratios
The second case study considers the realization of dedicated mixing ratios. Therefore, the Meander Designer was applied for generating for each design realizing
a specific mixing ratio two meanders. These two meander designs realize a fluidic
resistance ratio, which, eventually, implements a specific mixing ratio. For example,
to realize a mixing ratio of 1:1 of two fluids having the same properties, the
71
In order to extract the fluidic resistance R, additionally, the resistance M ii (Eq. 5.3)
of the input channel and periphery was measured. Therefore, the outputs Out1, Out2,
Out3, and Out4 were closed. Afterwards, the fluidic valves including the flow sensor
were connected one after another to the output Out5. Eventually, this allowed to
measure the overall resistance of R V , R tub , R valve , and R sens , i.e.
M ii = R V + R tub + R valve + R sens .
(5.3)
Having M i and M ii allowed to obtain the resistance of the meander (Eq. 5.4), i.e.
R = M i − M ii .
(5.4)
For measuring the resistances of the meander channels, water having a viscosity
of 1 mPa s was used. This water was driven by a pressure pump, which was
connected at input In. The pump applied increasing pressures ranging from 0 to
1000 mbar using a step width of 50 mbar. Similarly, the pressure was decreased
with the same step width. Each pressure value was fixed for 30 s and approximately
20 measurements were conducted in 1 s. This procedure was repeated for all four
meanders contained on the microfluidic device (i.e., only a single valve was open at
a time). Overall, this resulted for each of the considered fluidic resistances in a data
set containing the current time, the set pressure, the internal pressure, the resulting
volumetric flow rate, and the respective state of the fluidic valves.
For analyzing the obtained data set, a script allowed to split the data into blocks.
Here, a block contained the measurements for one dedicated pressure value (either
in the pressure increasing or decreasing phase) and one meander. Using such a
data block, the script allowed to determine the fluidic resistance by the quotient
between the pressure and the volumetric flow rate. Here, the median value of the
pressure/flow rate was used because this prevented that eventual spikes skew this
value in the measurements.
The results obtained by the different data blocks were afterwards further
aggregated: First, the median of the fluidic resistances was built separately for the
increasing and decreasing phase of the pressure for each meander. Overall, this
resulted in eight resistance values for the two phases and the four meanders on the
considered microfluidic device. Finally, again the median was built over these eight
values.
5.3.3 Setup for Realizing Dedicated Mixing Ratios
The second case study considers the realization of dedicated mixing ratios. Therefore, the Meander Designer was applied for generating for each design realizing
a specific mixing ratio two meanders. These two meander designs realize a fluidic
resistance ratio, which, eventually, implements a specific mixing ratio. For example,
to realize a mixing ratio of 1:1 of two fluids having the same properties, the