KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Subject: search.filters.subject.Dimensional analysis

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Design Optimization of CMOS- MEMS Staggered Vertical Comb Based Micro Scanners
    (2022-01-01)
    Chen, Wenhao
    ;
    Duani, Mingzheng
    ;
    Tavakkoli, Hadi
    ;
    Luo, Huahuang
    ;
    Zhao, Bin
    For the first time, we propose a novel CMOS-MEMS staggered vertical comb based micro scanner (SVC-MS) for ID static out-of-plane rotation using CanSemiconductor 0.18μm IP6M, TSMC CMOS foundry process. Based on compact model, the parametric analysis shows the torsion spring width and the actuator thickness are two critical parameters in term of design, and design optimization using dimensional analysis can be conducted for improving the rotation angle(Ooptical=19.26°) and figure of merit (FoM=O.6) by 400% and 150% compared with the first design. The optimized design shows miniaturization with a mirror size of 800μm and a higher FoM of 0.6 among previous designs. In addition, critical ratio of geometry for increasing the input-output response with a lower voltage is found, which can improve the actuator's performance.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Similarity model for estimating the error of clamp-on ultrasonic flowmeter: Flow in water supply piping system
    (2017-01-01)
    Sritham, Earasit
    ;
    Wachirapunyanont, Rathachot
    ;
    Siriparinyanan, Pontakorn
    ;
    Nunak, Navaphattra
    ;
    Suesut, Taweepol
    This study was aimed at presenting the similarity model for the estimation of error of a clamp-on, transit-time ultrasonic flow measurement. Dimensional analysis was based on the Buckingham Pi’s theorem. The groups of independent parameters that were taken into account for the analysis included pipe characteristic, fluid characteristic, and meter installation setting. Experimental testing section was fabricated using PVC pipes with diameters of 1-in and 2-in and 45º PVC elbows. Flow velocity was fixed at 0.5 m/s. The upstream and downstream distances were in the ranges of 2D-20D and 2D-10D, respectively. It was found that the upstream and downstream distances greatly affected the accuracy of the measurement. Larger relative errors were found from the measurement on the smaller pipe. With the installation of ultrasonic transducers according to the recommended value by FCI, the error obtained with the measurements on 1-in and 2-in diameter pipes were, respectively, 7% and 0.35%. The acceptable measurement ranges of upstream distance for 1-in and 2-in diameter pipes were 16D-20D and 6D-20D, respectively. The measurements on a 2-in diameter pipe with a downstream distance in a range of 4D-10D was acceptable. For the 1-in diameter pipe, any downstream distance less than 10D resulted in unacceptable error. The accuracy of measurement was more sensitive to the change of downstream distance than the change of upstream distance. The applicable range of the prototype prediction equation was greatly affected by the flow model. The equation obtained with a 1-in diameter flow model could only be used to predict a 2-in diameter prototype within a range of 18D-20D. Increasing the size a flow model could greatly broaden the applicable range the applicable range of the prediction equation. A 2-in diameter flow model could be used to predict a prototype upto 150 in.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Similarity Model of MWA Thailand Water System for Error Estimation of Ultrasonic Flow Meter
    (2017-01-01)
    Wachirapunyanont, R.
    ;
    Kongratana, V.
    ;
    Gulphanich, S.
    ;
    Suesut, T.
    ;
    Nunak, N.
    This paper proposed a similarity model of MWA water system using the dimensional analysis based on the theory of Buckingham Pi for error estimation of transit-time ultrasonic flow meter with clamp-on at different installation conditions. There were three main parameters groups, i.e., pipe characteristic, meter installation, and fluid characteristic and properties and could be arranged in five Pi terms, i.e. E×(L<inf>e</inf>/D), µ/ρvD, L<inf>e</inf>/D, U<inf>s</inf>/D and U<inf>s</inf>/D. The results showed that the relative errors of measurement increased with the decreasing of upstream and downstream of meter at the same velocity and there was a possibility to use the model to determine the correction factor to compensate the velocity measurement of ultrasonic flow meter as the installation could not comply with the requirement. However, the further experiments should be performed for validation of the model predictive equation i.e., E 0.3607 E <sup>.</sup> p m.