Wood Splitting Machine for Tea and Bakery Industries

In Sri Lanka, firewood is regarded as a common conventional fuel, mainly in food preparation purposes. Essentially due to economically availability, firewood has still been using as the main source to lit fire in rural areas. Other than for household food preparation, firewood is still the main source of generating heat in food related rural industries, such as tea factories, bakeries, hotels etc. In tea factories and in some of the bakeries, firewood is used in mass scales. Even tons of fire wood is used in each of them, per day. To make easy burning, the wood logs need to be cut in to small pieces. In almost all such places, wood splitting is done manually. It finds very difficult to split wood logs by using an axe. This needs time and more manpower. On the other hand, an additional cost is involved for workers’ payment. If the wood splitting can be mechanized, it may be huge beneficial for such industries as tea factories and bakeries etc. Therefore, this project is aimed to introduce a wood splitting machine, which has the specific objectives of efficient supply of usable level firewood at a shorter time with lower cost and without much manpower to split firewood logs. Lower maintenance requirement together with lower failure frequencies may be added advantages, when compared to the hydraulic devices [4].

Numerical Research of Pump-as-Turbine Performance with Synergy Analysis

The wide use of pumps and turbines has significant value in energy conservation and utilization. In this work, a three-dimensional Computational Fluid Dynamics (CFD) model and a one-dimensional theoretical model of a Pump as Turbine (PAT) were established. On this basis, the correlation between pressure and velocity was quantitatively investigated by a proposed sensitivity index (SPV). A synergy field analysis was then applied to evaluate the flow characteristics of a pump and PAT, providing a perspective from the mechanism of the energy transfer enhancement for hydraulic devices. Moreover, the hydraulic and synergy performances of PAT were studied under various operating conditions. The results show that the minimum SPV is obtained in the impeller. With increasing flow rate, the SPV of the PAT generally increases, and the synergy angle of the impeller surface increases as well. A strong disordered synergy field is observed in regions of the blade leading edge, trailing edge, and volute tongue. The variations in efficiency and head with flow rate showed similar trends, respectively, with the synergy angle of the outlet and the mid-plane. This study provides an analytical method for quantitative evaluation of flow synergy characteristics, and it supplies a basis for further design improvement of the pump and PAT.

Analytical studies on constrained particle settling velocity in a water suspension of fly ash from thermal power plants

Purpose. To establish analytical dependences for calculating the characteristics of the ash suspension and the velocity of constrained settling of coal and quartz depending on the particle size and density of the medium, which is necessary for calculating the design and determining the operating modes of hydraulic devices for extracting coal from water mineral suspension of fly ash from thermal power plants. Methodology. The research was carried out on the basis of a cellular suspension model and classical concepts of constrained particle motion in laminar and turbulent flow. For analytical evaluation of the characteristics of the suspension, the defining correlations and the Wend formula for viscosity were used. The Ergun equation and correlation analysis methods were used to calculate and analyze the speed of constrained movement of ash suspension particles. Findings. Approximating nonlinear functions are obtained for determining the speed of constrained movement of coal and quartz particle size up to 4 mm in an ash suspension with a density of 1.31.8 g/cm3. It is shown that, for both settling and ascending of coal, there is a direct relationship between the velocity and particle size, in both cases it is nonlinear. For any coal size, the speed of ascent depending on the suspension density is of extreme nature; the rational density range is 1.551.8 g/cm3 with a maximum of 1.65 g/cm3. The established dependencies allow us to determine the size of coal and quartz particles, taking into account the counter-flow of the liquid phase, as well as the boundary size. Originality. For the regime of weak-turbulence flows there were established dependences and approximation equations of the constrained movement speed of coal and quartz particles the main components of the water suspension of fly ash from the Novo-Kramatorska TPP, depending on the size and density of the ash suspensions with changes in the characteristics of the medium depending on density. The frames of the Stokes description of processes are established. It is shown that the movement of the liquid phase in a counter-flow with precipitating particles is effective for surfacing of thin coal classes. Practical value. The described approach can be used for analytical evaluation of the characteristics and velocity of constrained movement in various water suspensions of discrete solid particles in weak-turbulence flows. The advantage is a wider coverage of hydraulic equipment operating modes. The results obtained are necessary for designing and determining the technological modes of operation of various hydraulic devices in the technology of complex processing of fly ash from TPPs.

BENCH COMPLEX FOR SYNCHRONOUS MONITORING OF NOISE VIBRATION AND FUNCTIONAL CHARACTERISTICS OF ELECTROHYDRAULIC EQUIPMENT

When creating specialized pumping test stands for hydraulic devices to check their vibration and noise characteristics, the main problem is the choice of pump type. This, in the first place, is connected with the different principle of operation of pumping units and the influence that the working organ exerts on the flow of liquid.Currently, there is a wide range of pumps, differing in design, with different functional capabilities, supplying the working medium both at the nominal mode, and allowing to regulate supply and pressure parameters in a wide range. They are divided into two main groups: dynamic and voluminous. The choice of the pump for the needs of creating a stand determines its own vibra-tion characteristics of the entire system being created.Proceeding from the made choice, it is necessary to determine the own charac-teristics of the created stand and, if necessary, to develop and apply a number of additional tools that allow improving the vibrational and noise characteristics of the stand being created.The article presents the procedure for creating such a stand and describes the solutions that allow to combat the influence of the pump unit during the testing of hydraulics. The work was carried out using two types of pumps: axial-piston and centrifugal pumps. The following solutions were applied in the work: resonators, vibra-holding arrays, expansion tanks and flexible interchanges. The selection of the optimal combination and the correct calculation of the parameters of these means can significantly improve the intrinsic characteristics of the test stand being created and reduce own noise in the part of vibration and hydrodynamic noise.

DYNAMIC CHARACTERISTICS CALCULATION FOR ELECTRO-HYDRAULIC CONVERTER OF NOZZLE-FLAP TYPE FOR MODERNIZATION OF SYSTEM FOR MOTOR-CAR FUEL FEEDING CONTROL

At the current stage of the development of means for automatic control for the formation of qualitative systems of machines, construction and road machinery, railway transport there are used electro-hydraulic devices transforming electric input signals into hydraulic output power. To carry out a generalized analysis and for the fulfillment of the preliminary synthesis of an automated hydraulic system on the whole the static and dynamic characteristics of its separate units should be obtained. In the paper there is presented a calculation of a theoretical dynamic characteristic of the electro-hydraulic nozzle-flap converter to substantiate potentialities of its inclusion as an adjusting device acting upon rods of a high-pressure fuel pump in the system of fuel feeding control of a KamAZ motor-car engine. At that the converter was considered as interconnected units: a unit of feedback. The methods of the investigation of processes in the converter are based on the fundamentals of the theory of automatic control. As it follows from the transition function diagram obtained as a result of the investigations carried out the transition time of a electro-hydraulic converter slide valve movement from a neutral position into an extreme one in the course of sending a maximum control signal to the coil does not exceed 1.1 sec, that is satisfactory for the formation of hydraulic drive control systems.