the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 01 Oct 2024
Design of Wide Particle Size Range Aerodynamic Inlet System with New Pre-focus Structure
Abstract. A new aerodynamic lens injection system has been designed for wide particle size range, which adds virtual impact and pre-focus structure on the basis of traditional PM2.5 lenses. The system has a small volume and successfully improves the focusing ability of traditional PM2.5 lens systems to 100 nm–10 μm. The structure of the new pre-focus hole solves the problem of affecting the transmission and focusing of large particles, effectively reducing the beam width and dispersion angle of particles entering the virtual impactor, significantly improving the focusing effect of large particles, and enhancing the transmission efficiency of large particles. It can also effectively focus particles without significantly accelerating particles, avoiding the structural size of the buffer chamber being too large. Numerical simulation shows that the new injection system can transmit particles with 100 % efficiency in the range of 0.2–4 μm particles, and can achieve the transmission of 1–9 μm particles with an efficiency higher than 90 %. The standard microsphere experiment verified the good consistency between the performance of the injection system and the simulation results. In the testing of standard Arizona dust, the wide-range particle size distribution obtained by the new injection system is highly consistent with APS 3321. The new injection system combines a new pre-focus structure, a smaller buffer chamber, a five-stage lens, and the whole injection system volume that is up to 90 % smaller than previous self-made wide-range lens designs. At the same time, it has ultra-high transmission efficiency, demonstrating the potential for miniaturization of single particle aerosol mass spectrometer in detecting particles with a wide particle size range.
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Status: final response (author comments only)
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RC1: 'Comment on egusphere-2024-2577', Anonymous Referee #1, 25 Oct 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2577/egusphere-2024-2577-RC1-supplement.pdf
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RC2: 'Comment on egusphere-2024-2577', Anonymous Referee #2, 06 Nov 2024
This paper describes a new design for an aerodynamic lens system that transmits a broad range of particle sizes from 100 nm to 10 microns. The design was evaluated with CFD modeling and experimental measurements of transmission efficiency. This is an important development for instruments that sample with an aerodynamic lens system. However, the paper is not well written. It might be suitable for publication after addressing the following issues. It needs to be reviewed again.
This paper needs to be carefully edited by a native English speaker who is a good writer. There are many instances of incomplete sentences (e.g., lines 55-57), run on sentences, repetitive language (e.g., lines 47-51), missing words (e.g., line 60), misused words (e.g., “on” instead of “of” in line 63), and muddled language (e.g., lines 298-299) The overall effect is that the paper is confusing.
The introduction would benefit from a brief description of what the parts of the inlet system/aerodynamic lens are and what each one does. such as the critical orifice, the buffer region, the apertures in the aerodynamic lens, etc. It would also help if the nomenclature is consistent between the figures and the text and between different parts of the text. Each part that is called out in the text should be labelled in Figure 1. For example, a virtual impactor is mentioned in line 139 but I can’t tell if that is the same thing as the pre-focus hole or the buffer chamber in Figure 1 or something else entirely. Where is the critical orifice and what diameter is it?
What is the pressure in each stage of the inlet? What does “low-pressure loss” mean in lines 106-107?
The authors mention multiple times that their goal is miniaturization of the SPAMS. Making the inlet smaller is not going to accomplish that. The size is really determined by the pumps and the mass spectrometers. It is ok to say that the goal is to extend the range of sizes transmitted by the inlet system.
The abstract is confusing. There are multiple size ranges and it is not clear how they relate to each other. There are yet more size ranges in lines 110-113.
I do not understand how you can count PSL particles with the CPC without also counting the surfactant particles from the atomized solution.
Lines166-170: What wavelength is the laser and what is the smallest size particle that can be detected?
Lines 183-185. Are the authors saying that all of those references added a buffer chamber and a virtual impactor? That is not true. Please read those papers and cite them correctly.
Figure 3. The legend is confusing. Put the year in for Du et al. Are the bottom three all from the present study with different configurations? Or from previous studies? It is not clear.
Line 212: What is a “strong” buffer?
Figure 4. What does the axial velocity impact in terms of particle transmission? What part of the diagram in Figure 1 does the grey box correspond to? Does it really make a difference that the blue line has a few wiggles in the grey box? The transmission efficiency shown in Figure 3 is the same for Du et al. and present study for those sizes. Do the authors have data for 9 or 10 micron particles? That would be more relevant since there is a difference in transmission efficiency.
Figure 5. Why show both 5 and 6 micron particles? They are very similar. Panels a) and c) are both the “new” system but have different structures in the inset. Why? It’s not clear what the authors are referring to with “new” and “old.” Is “old” Du et al.? How does the structure in panel e} relate to Figure 1? They look different.
Figure 6. I would not label every point with its value. I think it makes the figure too busy. It would be better to put the data values in a table. Same comment for Figure 7. Scale the y-axis in Figure 7 from 0.
Line 260: Why place the target 11 cm downstream?
Lines 286-287. The authors do not know this. It is very common for experimental measurements of transmission efficiency to be different from calculations.
Line 309: What do the authors mean by “the 2.5 micron lens system?” Is this the same thing as the “aerodynamic five stage lens group” on line 121 and the “PM2.5 five stage lens” on line 271? Please use consistent names throughout the paper.
A few minor comments:
Line 287: What is the B-SPAMS? Is it the same instrument mentioned previously? Then use the same acronym. Same comment for line303.
Line 146: Define DPM
Line 291: Do not capitalize ULTRAFINE TEST DUST. Define APS. Give manufacturer and model.
Citation: https://doi.org/10.5194/egusphere-2024-2577-RC2
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