Simulation of lubricating oil centrifugal separator performance index influence on marine diesel engine wear

Представлена методика подбора центробежного сепаратора для комбинированных систем тонкой очистки моторного масла в двигателях внутреннего сгорания. Предложен показатель (индекс производительности сепаратора), который характеризует интенсивность разделения гетерогенных систем центрифугированием. Показана зависимость скорости изнашивания основных деталей дизеля от качества используемых горюче-смазочных материалов и интенсивности очистки масла (индекса производительности сепаратора). Рассмотрены преимущества комбинированной системы очистки смазочного масла, включающие в себя центробежный сепаратор, обеспечивающий очистку масла от нерастворимых загрязнений мелкодисперсной фазы работающий совместно с саморегенерирующимся фильтром. Благодаря такому сочетанию обеспечивается минимальной изнашивание пар трения дизеля. Преимущество данного метода очистки также заключается в возможности обеспечения автономной работы механизмов смазочной системы при сохранении высокой эффективности очистки. С помощью экспериментального моделирования определено минимальное значение индекса производительности центробежного сепаратора, необходимое для стабилизации изнашивания деталей дизеля и достижения ресурсосберегающего маслоиспользования. Проиллюстрировано сравнение результатов моделирования с экспериментальными данными. Methods of centrifugal separator selection for lubricating oil combined purification systems of internal combustion engines are represented. Purification intensity parameter (performance index) for description of heterogeneous medium separation is offered. The relation between separation intensity (separator performance index) and engine wear is shown as well as its dependence on fuel and lubricating oil quality. Advantages of lubricating oil combined cleaning method by means of centrifugal purifier, used for insoluble particles removal together with the self-regenerating filter are represented. Due to their combination the minimum wear of diesel engine friction coupling can be achieved. Benefits of the method lie in autonomous operation of lubricating system for a long period of time together with high purification efficiency. Minimum value of separator performance index, required to stabilize engine parts wear and achieve resource-saving oil use has been determined by means of experimental design. Simulation results have been compared with experimental data and effect of comparison has been represented.

Numerical simulation of the dynamics of dust in a rotary dust collector with an adjustable air flow

A rotary dust collector has been developed that works on the principle of a centrifugal separator. A feature of its design is the presence of a bypass recirculation channel of cleaned air with a flow regulator, two outlet pipes with flow uncoilers in the form of spiral channels. The calculation of the motion of dust particles with a density of 3000 kg/m3 and a diameter of 1 to 100 microns has been performed. Research has been carried out to improve the efficiency of the apparatus using a central compositional plan and to establish rational design and operating parameters of the mixer for recirculating and purified air.

Comparison of turbulence models for two-phase flow in a centrifugal separator

The numerical results of mathematical modeling of a two-phase, axisymmetric swirling turbulent flow in the separation zone of a centrifugal separator are presented. The movement of the carrier gas flow was modeled using RANS, which were closed using the SARC turbulence models, the SST-RC model, and the SSG/LRR-RSM-w2012 model. For the numerical solution of the problem, the SIMPLE algorithm was used. The article compares the results of numerical calculation of turbulence models. The results of a comparison of numerical calculations with allowance for the effect of the solid phase on the dynamics of the air medium and without taking it into account with experimental data are presented.

MATHEMATICAL MODELING OF A TURBULENT FLOW IN A CENTRIFUGAL SEPARATOR

The numerical results of mathematical modeling of a two-phase axisymmetric swirling turbulent flow in a separation zone of a centrifugal separator are presented. The motion of the carrier gas flow is described by the Reynolds-averaged Navier-Stokes equations. A system of equations is enclosed by the Spalart-Allmaras turbulence model. The study is based on the obtained fields of averaged velocities of the carrier medium, with account for turbulent diffusion. Numerical solution to the problem is implemented using the semi-implicit method for pressure linked equations (SIMPLE). The results obtained when the solid phase effect on the air flow dynamics is taken into account are compared with those obtained when the effect is left out of account. The numerical calculations are validated using the experimental data.

Milk Cholesterol Reduction at Pilot Station Level Using Beta-Cyclodextrin

The objective of this study was to investigate the possibility of cholesterol elimination from milk using beta-cyclodextrin at pilot station scale, because there is very little information considering this level of milk processing. β-cyclodextrin is a nontoxic, edible and chemically stable compound with affinity for nonpolar molecules like cholesterol, giving the opportunity for obtaining food products that can prevent the appearance of cardiovascular diseases. By applying of this procedure, the cholesterol reduction percentage was calculated as approximately 84 %, similar to the values reported by the specialty literature. Except fat and freezing point values, the other parameters values increased with an approximate percentage of 8, indicating a concentration phenomenon due to milk pasteurization. Fat concentration value decreased with 5.9 %, due to the cholesterol inclusion in the beta-cyclodextrin molecule and its elimination at the bottom of the centrifugal separator. However the variation of the parameters is insignificant, so this process could be considered efficient to be applied at a pilot station level.

Modeling and Design of a Controller for a Dehumidifier

Many industries like pharmaceutics, plastics, food and confectionery, tobacco and cold storage, maintaining the humidity at the desired level is very important. The aim of this paper is to process the model and to design a controller for a dehumidifier to control the humidity at the desired set point. The air is humidified using a humidity chamber. This humid air which is the primary air is mixed with secondary air from the compressor and sent to the dehumidifier. The dehumidifier used here is a centrifugal separator. The humidity of the dehumidified air is measured using a sensor. The output signal of the sensor is compared to the set point. If the output measured exceeds the set point, accordingly the flow rate of the secondary air to the dehumidifier is varied until it reaches the desired set point .The model of the process is identified from the response of the process to the input signals. The controller is designed for the model obtained and the performance of the controller based on the time domain specification is compared.