Wattananusorn, Santi
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Wattananusorn, Santi
Alternative Name
Wattananusorn, S.
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santi.wa@kmitl.ac.th
12 results
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Item type:Publication, CFD prediction of mixing performance for circular and non-circular jet mixing tanksOur previous CFD predictions of the circular, elliptic, and square jet mixing tanks were re-analyzed to investigate the highest performance jet mixing tank design and the appropriate mixing performance criterion. So, the mixing performance indicated by overall mixing time and maximum mixing time criteria of these jet mixing tanks was compared. These CFD predictions were carefully developed by using our previous reliable jet mixing tank CFD model. For model validation, reasonable agreement between the predicted mixing times and measurements was observed. The results revealed that circular and non-circular jet flow phenomena were significantly different in the near field jet regions. Further, the elliptic jet mixing tank provided the highest mixing performance because of its highest entrainment and turbulence kinetic energy near the jet boundary. Finally, it can be concluded that the maximum mixing time criterion is a suitable mixing performance indicator. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Bench scale production of vitamin e from crude palm oil(2021-01-01); Kitchaiya, PrakobVitamin E (VitE) from palm oil is usually separated from palm fatty acid distillate. VitE separation from crude palm oil (CPO) has been rarely reported. This work presents a separation of VitE from CPO in a bench scale process to attain a high concentration of VitE oil by methanol extraction, followed by fatty acid esterification and glycerides transesterification in the extract, and finally concentrated by high vacuum evaporation of fatty acid methyl esters. The starting content of VitE in CPO was 887 ppm, which was first extracted with an equal mass of methanol and evaporated to gain 4,515 ppm of VitE in the evaporated extract. The extract was esterified and transesterified to convert free fatty acids and glycerides into fatty acid methyl esters. The bulk of methyl ester was evaporated under high vacuum using Kugelrohr apparatus and the oil residue contained 69,950 ppm VitE, which was 80 times the original amount in CPO. By this development, 80 wt.% of VitE remains in the extracted CPO as a natural antioxidant and the CPO can be normally purified as edible palm oil or used as feed stock for biodiesel production. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, CFD modelling of pump-around jet mixing tanks: a discrepancy in concentration profiles(2018-10-03); ; Jet mixing tanks are important in chemical processes. Over the past two decades or so, computational fluid dynamics (CFD) has been employed to study jet mixers. The shortfalls of the previous CFD models were the discrepancy in concentration profiles between simulation and experiment and the absence of exact inlet turbulence conditions. So, in our present work, the CFD model was developed to investigate the proper conditions for jet mixing tank simulation and improve the accuracy of concentration profile prediction by using an appropriate grid arrangement, a realizable k-epsilon model, and a second-order upwind discretization scheme. The results revealed that the CFD model with proper inlet conditions predicted the overall mixing time well and somewhat improved the predicted concentration profiles. Further, the reasons for discrepancies in concentration profiles were inappropriate inlet turbulence conditions and overprediction in total momentum available for mixing due to the flat top liquid surface assumption. In addition, this discrepancy may be caused by the dynamic response of concentration measuring device. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, On the Semi-Analytical Solution of Displacement Thickness in a Laminar Streamwise Corner Flow Assisted by Computational Fluid Dynamics Simulation(2023-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Explicit analytical solution for drying kinetics of flat materials(2009-02-01)This research features a theoretical framework to describe the transport of moisture content in convective drying of flat materials. A new set of formulations is developed on the basis of the spreading-pressure concept as the driving force rather than using the traditional Fick's law. The suggested method also provides a possibility to abandon both conventional isotherms: the two-parameter Brunauer-Emmett-Teller (BET), and the three-parameter Guggenheim-Anderson-de Boer (GAB) models. As a result, the proposed procedure creates a moisture dependent diffusivity embedded in a certain non-linear diffusion equation which can be solved explicitly. © 2009 Pleiades Publishing, Ltd. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, New space-averaging procedure for inhomogeneous flow fields using balance equation formulations(2006-09-01)This paper features the possibility of averaging space-dependent flow fields using a coupling factor that links the equations of momentum and energy. The scheme is applied to the mean velocity, which is derived straightforwardly through the continuity equation. It creates a small imbalance, which can be eliminated later completely. Smaller discrepancies in the integration of systems of balance equations for inhomogeneous flow are the consequence. The procedure is verified on various flow patterns, and comparisons are made with other conventional methods and with some available experimental data. Despite investigating only numerical examples of incompressible flows here, the technique, in principle, is capable of dealing with compressible flows as well. Furthermore, the proposed method discards some variables required in other techniques while still providing useful and acceptable results for practical problems. © IMechE 2006. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Determination of membrane resistance for cross-flow microfiltration in a rectangular module including back-flow(2008-01-01)In the current note, the previously developed semiempirical models are incorporated, based on blocking filtration laws, with an approach by using a higher-order pressure function over the membrane surface providing the local non-linear characteristic of the transmembrane pressure during discontinuous semibatch processes. Consequently, the flux predictions of a continuous cross-flow microfiltration system with back-flow across a membrane module are appropriately modified for more accurate formulations of membrane resistance. © IMechE 2008. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, How Can an Appropriate CFD Model be Developed for Turbulent Flow in Rough Pipes?: Evidence from Friction Factor Prediction(2026-01-01); This paper answers the question: “How can an appropriate turbulent rough pipe flow computational fluid dynamics (CFD) model be developed?” The Reynolds-averaged Navier-Stokes equations with the standard k-epsilon turbulence model and scalable wall functions were solved to obtain Fanning friction factors and mean velocity profiles in inflectional and monotonic rough pipes. CFD models with near-wall grid sizes from four dimensionless wall distances and two roughness treatment approaches were simulated. Eight roughness Reynolds numbers, covering the lower end of the transitionally rough regime through the fully rough regime, were studied for each roughness type. Appropriate roughness and turbulence model constants for turbulent rough pipe flows in the transitionally rough regime were determined. For model validation, the predicted mean axial velocity profiles for Reynolds numbers of 5 × 10<sup>4</sup> and 5 × 10<sup>5</sup> exhibited good agreement with the reference experimental data. A total of 208 CFD simulations (32 from our previous works and 176 from the present study) were analyzed. Finally, based on comparisons between predicted Fanning friction factors and established correlations, appropriate CFD models for turbulent flows in inflectional and monotonic rough pipes were identified. Suitable CFD models for accurately predicting mean velocity profiles at roughness Reynolds numbers below 11.225 were also obtained, although with the caution that improved mean velocity prediction may reduce Fanning friction factor accuracy. Furthermore, the present CFD work provides essential guidance for extending simulations to other rough surface types and rough-wall flow situations. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, CFD modelling of pump-around jet mixing tanks: a reliable model for overall mixing time prediction(2019-07-04); Over the past two decades or so, computational fluid dynamics (CFD) has been employed to predict overall mixing times inside jet mixing tanks instead of non-universal mixing time correlations obtained by experiments. However, the numerical methods for jet mixing tank simulations were not clearly tested and the discretization errors of the previous CFD models were not assessed. So, in this paper, the suitable turbulence model and numerical methods for pump-around jet mixing tank simulations were investigated. Further, the discretization errors of the present CFD models were estimated with the help of grid convergence index (GCI). The results revealed that the realizable k-epsilon model, SIMPLE, second order upwind, and first order implicit were proper turbulence model and numerical methods for pump-around jet mixing tank simulations. From GCI analyses, the maximum discretization uncertainty in overall mixing time of the present CFD models was about ±0.08 s. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Investigation of entrance length in circular and noncircular conduits by computational fluid dynamics simulation(2014-01-01); This study estimated entrance length of circular and noncircular conduits, including circle, triangle, square and hexagon cross-sectional conduit, by using computational fluid dynamics (CFD). For simulation condition, the length of non-circular conduit was 10 m and the hydraulic diameter was 0.2 m. The laminar flow with Reynolds number of 500 and turbulent flow with Reynolds number of 50,000 were applied to investigate water flow in conduits. The governing equations were solved iteratively by using ANSYS FLUENT 14.0. For turbulent flow simulation, standard k-epsilon and RNG k-epsilon model were employed to simulate turbulence. The preliminary results were validated by comparison with theoretical data. At first, grid independency was evaluated to optimize the model. Norm* was employed to investigate the entrance length, which is related to velocity. The simulated results revealed that the entrance length for laminar flow was longer than turbulent flow.