Experimental Study on the Effect of Waste Valve Load and the Volume of Air Chamber on the Performance of the Hydraulic Ram Pump (Hydram) to Water the Paddy Field in Pakandangan, Padang Pariaman Regency

This 2019 DIPA Grand’s research designed and fabricated the size of hydraulic ram (hydram) pump utilized in Pakandangan, Padang Pariaman Regency. There is a water source in this area which has not been functioned adequately to irrigate the paddy field of 10 hectares due to the location of the paddy field which is higher than the water source. However, the use of designed hydram pump has no been maximized as the pump’s optimal performance was not determined yet. Therefore, a hydram pump was designed by varying the load of waste valve in the weight of 400 g, 600 g, 800 g, 1,000 g, and 1,200 gr. It was also varied in the volume of the chamber when the pump operated which were 4.86 lt, 5.76 lt, 6.48 lt, 7.29 lt, and 8.1lt. The height (Hd) of the inlet pipe was 1 m, and the lift height (Hs) of the outlet pipe was 5 m. The results obtained from Pump performance increases with increasing cylinder volume. The increase in the load of the exhaust valve volume of the tube remains a significant decrease. Hydram pump performance occurs at a load of 400 g with a tube volume of 8.1 l with an efficiency of 53%

Numerical Simulation of Internal Flow Field in Turbo-Expander

As everyone pays more attention to energy consumption, it is very meaningful to use natural gas pressure energy for power generation and turbo-expander is an important part of power generation devices. In this paper, the turbo-expander model for pressure energy generation is meshed and numerically simulated based on fluent, and the pressure distribution and velocity distribution in the turbo-expander are obtained. The volute profile is Archimedes spiral, and the impeller is modeled by cfturbo. The main conclusions are as follows: when the number of grids is more than 2.2 million, the simulation results are less affected by the number of grids. The internal basin of the turbo-expander has obvious pressure gradient and velocity gradient. Due to the negative pressure at the elbow of the inlet pipe of the centrifugal effect, the existence of the blade leads to the change of the flow direction. Different watershed planes have different pressure and velocity distributions. The velocity and pressure of the watershed plane near the impeller outlet and the volute outlet are often smaller, but the flow vortex is more intense.

Research on Visualization of Inducer Cavitation of High-Speed Centrifugal Pump in Low Flow Conditions

Inducer is often used to improve the cavitation performance of pump. In order to study the cavitation characteristics of inducer under low flow condition of high-speed pump, high-speed photography technology was employed in this paper to carry out visual experiments on the inducer of a high-speed centrifugal pump. In low flow rates, Cavitation distribution and evolution among the inducer were captured. The experimental results revealed that a band-shaped backflow vortex in the inlet pipe would occur when the flow rate was less than 0.3 Qd. Moreover, the backflow vortex in the inlet pipe rotated with the inducer and the rotational speed of backflow vortex was approximately half of the inducer. The visualization test of 0.27 Qd was carried out: when the NPSH was greater than 6.72 m, the bubbles in the inlet pipe were asymmetrical; When the NPSH dropped to 5.41 m, the cavitation was becoming less asymmetrical; When NPSH dropped to 3.81 m, cavitation evolved to the deteriorating stage, plenty of bubbles entered into the main impeller, resulting in a rapid decline of pump performance. Furthermore, the cavitation performance was worse at an extreme flow rate, and the NPSH value of 0.27 Qd was 7.5% greater than that under design condition.

Influence of asymmetric airflow on the cooling performance of brake disc of railway vehicle

The main objective of this article is to discuss the influence of asymmetric airflow on the cooling performance of the brake disc. This asymmetry might be caused by the air inlet pipe curvature of the UIC test bench for frictional components, whereas in reality this asymmetry might be caused by various factors. In the first part of the paper, a brief summary of effects of heat and temperature changes on the brake disc is presented. Additional information about UIC test bench is given with the focus on cooling effects of airflow on the disc. In the second part, a CFD simulation was made, and its settings and results are presented in detail. In the last part, temperature differences in various time points and positions on the brake disc are compared graphically in order to assess the influence of airflow from the inlet pipe and its curvature on the cooling performance of the brake disc.

Modification and Performance Evaluation of a Floating Drum Biogas Digester

Biogas is a renewable source of energy that is obtained from the anaerobic digestion of agricultural residues, animal dung, energy crops, domestic wastes and industrial wastes. These categories of waste that produce biogas are promising sources of energy and the biotechnology process of biofuel is environmentally friendly. This study aimed at modifying, fabricating and evaluating a floating drum digester. The modified floating drum digester consists of the digester tank, gas holder tank, feeding inlet pipe, gas collector outlet, slurry outlet, thermometer and hose. The gas holder tank was inserted into the digester tank while the biogas is generated in the digester tank by pressure. The biogas was produced from the mixture of cattle dung 30 % and 50 % plant wastes. Hence, the organic waste mixed with water in the ratio of 1: 2 for the digestion process. The digestion temperature was recorded daily for a period of 21 days at constant pressure of 1.32 KN/m2 throughout the experiment. The result revealed that the minimum and maximum average temperatures are 25 to 33 oC. This shows that the ambient temperature affects the temperature in the digester and the amount of gas produced is a function of the accumulated temperature in the digester. It was observed that the biogas generated increase as temperature rise. The modified floating drum digester is affordable and it is recommended for small- and large-scale production.