TAN et al 2020a - Revision history

Rimni: /* 3.4 Effect of Particle MVD */

2021-12-14T15:14:27Z

‎3.4 Effect of Particle MVD

Rimni at 15:14, 14 December 2021

2021-12-14T15:14:05Z

Rimni at 15:13, 14 December 2021

2021-12-14T15:13:41Z

Rimni at 13:34, 29 January 2021

2021-01-29T13:34:51Z

Rimni: /* Conflicts of Interest */

2021-01-29T13:33:55Z

‎Conflicts of Interest

Rimni at 14:12, 25 January 2021

2021-01-25T14:12:06Z

Rimni: /* 3.4 Effect of Particle MVD */

2021-01-25T14:10:40Z

‎3.4 Effect of Particle MVD

Rimni at 14:08, 25 January 2021

2021-01-25T14:08:24Z

Rimni at 14:05, 25 January 2021

2021-01-25T14:05:52Z

Rimni at 14:03, 25 January 2021

2021-01-25T14:03:59Z

@@ Line 458: / Line 458: @@
 |}
-===3.4 Effect of Particle MVD===
+===3.4 Effect of particle MVD===
 Finally, the effect of initial particle MVD on variables are obtained. [[#tab-4|Table 4]] shows the cases of different MVD.

@@ Line 397: / Line 397: @@
 |}
-===3.3 Effect of Relative Humidity===
+===3.3 Effect of relative humidity===
 Similarly, to understand the effect of initial RH on the variables at engine inlet, only change the RH value at spray mast and keep the remaining conditions unchanged. The specific cases of different RH are shown in [[#tab-3|Table 3]].

@@ Line 118: / Line 118: @@
 A three-dimensional particle trajectory calculation model based on Eulerian method is established to obtain the thermodynamic coupling of particles and flow field without considering the solid-liquid mixing phase. NRC small ice tunnel in Ottawa was numerically studied based on the three-dimensional model. And the effects of different initial LWC, relative humidity and MVD were studied.
-==2. Description of the Model  ==
+==2. Description of the model  ==
 The air flow field is first calculated by the Spalart-Allmaras turbulence model [18], and the calculated results are used as known conditions for particle trajectory calculation.

@@ Line 546: / Line 546: @@
 This research was funded by the Open Fund of Key Laboratory of Icing and Anti/De-icing (Grant No. 1901IADL20190306).
-===Conflicts of Interest===
+'''Conflicts of Interest''': The authors declare no conﬂicts of interest.
-−
 The authors declare no conﬂicts of interest.
 ==References==

@@ Line 546: / Line 546: @@
 This research was funded by the Open Fund of Key Laboratory of Icing and Anti/De-icing (Grant No. 1901IADL20190306).
-==Conflicts of Interest==
+===Conflicts of Interest===
 The authors declare no conﬂicts of interest.

@@ Line 493: / Line 493: @@
 With the same initial LWC, increasing the MVD of particles reduces the amount of particles and the total surface area of contact with air which reduces the total amount of evaporation.
-Therefore, the larger the initial MVD of particles, the less LWC loss at the engine inlet ([[#img-5|Figure 5e]]), and the smaller the change of MVD due to the influence of evaporation on particle diameter (Fig. 5d). However, the LWC variation [javascript:; trend] of case 33 in [[#img-5|Figure 5e]] is particularly noteworthy. Which decreases slowly and then increases again. This is caused by the inertia of particles.
+Therefore, the larger the initial MVD of particles, the less LWC loss at the engine inlet ([[#img-5|Figure 5e]]), and the smaller the change of MVD due to the influence of evaporation on particle diameter ([[#img-5|Figure 5d]]). However, the LWC variation [javascript:; trend] of case 33 in [[#img-5|Figure 5e]] is particularly noteworthy. Which decreases slowly and then increases again. This is caused by the inertia of particles.
 [[#img-6|Figure 6]] shows the LWC comparison of case 33 and reference case. the particles of case 33 are difficult to change the direction of motion in the straight section of the wind tunnel due to its large particle diameter and large inertia. Therefore, a shadow zone is formed on the wall of the straight section, and the particles concentrate towards the center of the flow field, resulting in an increase of LWC at the central axis.

@@ Line 481: / Line 481: @@
 |  style="text-align: center;"|31
 |-
-|  style="text-align: center;"|MVD (μm)
+|  style="text-align: center;"|MVD (<math>\mu</math>m)
 |  style="text-align: center;"|10
 |  style="text-align: center;"|20

← Older revision		Revision as of 14:08, 25 January 2021
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−	One of the test conditions in paper [16] is as follows: air flow velocity at spray mast is 4.8 m/s; initial temperature is 273.15 K; relative humidity is 31%; particle LWC is 0.99 g/m3; particle MVD is 15.1 μm; pressure at engine inlet is 101.35 kPa; thermodynamic boundaries at walls are adiabatic. From the experimental results, the MVD of the particles at the engine inlet is 22.8 μm. MVD of particles increases in the strong evaporation environment, which seems to violate the law of mass conservation, but the results are in line with the actual engineering. This is because the particles ejected by the spray master are not exactly the same size, with an average diameter of 15.1 μm. In the process of evaporation, the diameter of all particles becomes smaller, but the size of smaller particles becomes smaller after evaporation, and then cannot be detected by the [javascript:; measuring] [javascript:; equipment], thus indirectly increasing the MVD value at the engine inlet [16]. However, there is no problem of data acquisition in the numerical simulation. In order to match the relative humidity at the engine inlet, the boundary conditions are the same as those of the experiment, but particles with same diameter which are 20μm are used as the initial condition, and the initial temperature of the particles is defined as 293.15 K.	+	One of the test conditions in paper [16] is as follows: air flow velocity at spray mast is 4.8 m/s; initial temperature is 273.15 K; relative humidity is 31%; particle LWC is 0.99 g/m3; particle MVD is 15.1 <math>\mu</math>m; pressure at engine inlet is 101.35 kPa; thermodynamic boundaries at walls are adiabatic. From the experimental results, the MVD of the particles at the engine inlet is 22.8 <math>\mu</math>m. MVD of particles increases in the strong evaporation environment, which seems to violate the law of mass conservation, but the results are in line with the actual engineering. This is because the particles ejected by the spray master are not exactly the same size, with an average diameter of 15.1 <math>\mu</math>m. In the process of evaporation, the diameter of all particles becomes smaller, but the size of smaller particles becomes smaller after evaporation, and then cannot be detected by the [javascript:; measuring] [javascript:; equipment], thus indirectly increasing the MVD value at the engine inlet [16]. However, there is no problem of data acquisition in the numerical simulation. In order to match the relative humidity at the engine inlet, the boundary conditions are the same as those of the experiment, but particles with same diameter which are 20μm are used as the initial condition, and the initial temperature of the particles is defined as 293.15 K.

	It is shown that the calculated results are quite consistent with the experimental results from the comparison of parameters in [[#tab-1\|Table 1]]. In addition, from the comparison of temperature fields in [[#img-2\|Figure 2]], it can be found that the temperature of the background flow field at the engine inlet decreases significantly due to evaporation.		It is shown that the calculated results are quite consistent with the experimental results from the comparison of parameters in [[#tab-1\|Table 1]]. In addition, from the comparison of temperature fields in [[#img-2\|Figure 2]], it can be found that the temperature of the background flow field at the engine inlet decreases significantly due to evaporation.

@@ Line 255: / Line 255: @@
 {| style="text-align: center; margin:auto;"
 |-
-| <math>C_D=\lbrace \begin{array}{c}
+| <math>C_D=\left\{ \begin{array}{c}
 \left(1+0.15{Re}_p^{0.687}\right)/{Re}_p,\mbox{ }{Re}_p\leq 1300\\
 .44,{Re}_p>1300
-\end{array}</math>
+\end{array}\right.</math>
 |}
 | style="width: 5px;text-align: right;white-space: nowrap;" | (12)
@@ Line 284: / Line 284: @@
 | style="width: 5px;text-align: right;white-space: nowrap;" | (14)
 |}
 ==3. Case study ==

@@ Line 594: / Line 594: @@
 [19] Crowe C., Sommerfeld M.,  Tsuji Y. Multiphase flows with droplets and particles (2nd edition). CRC Press, New Youk, 2002.
-[20] Zhang Y., Ozcer I., Nilamdeen S., Baruzzi G.S. et al. Numerical demonstration of the humidity effect in engine icing. SAE Technical Paper 2019-01-2015, 2019. Doi: [https://saemobilus.sae.org/content/2019-01-2015|  10.4271/2019-01-2015] https://doi.org/10.4271/2019-01-2015
+[20] Zhang Y., Ozcer I., Nilamdeen S., Baruzzi G.S. et al. Numerical demonstration of the humidity effect in engine icing. SAE Technical Paper 2019-01-2015, 2019. https://doi.org/10.4271/2019-01-2015
 </div>