Hydraulic machinery

About: Hydraulic machinery is a research topic. Over the lifetime, 34190 publications have been published within this topic receiving 153453 citations. The topic is also known as: hydraulic equipment & fluid energy machine.

A Model-Driven Scheme to Compensate the Strain-Based Non-Intrusive Dynamic Pressure Measurement for Hydraulic Pipe

Abstract: Strain-based non-intrusive approaches for measuring the pressure of pipes have attracted widespread attention due to their great convenience and ability to avoid destroying the integrity of structures. However, the mentioned method usually measures the dynamic pressure based only on the static strain–pressure sensitivity coefficients (SSSCs) instead of the dynamic strain–pressure sensitivity coefficients (DSSCs) due to its complicated calibration, which will inevitably affect the accuracy significantly. To address this issue, a model-driven scheme with dual stages is proposed in the present study to compensate the dynamic pressure measurement. The DSSCs are analytically derived for the first time from the axial governing equations of the pipe, considering the general boundary conditions for the thin-walled and thick-walled pipes simultaneously. In the first stage, the physical parameters involved in the DSSCs are calibrated by minimizing the residual of the experimental results and the theoretical counterparts. In the second stage, the DSSCs calculated from the calibrated analytical model are utilized to compensate the dynamic pressure based on the relationship between the DSSCs and the SSSCs. The proposed method is applied to an industrial hydraulic pipe system, and the experimental results show that the relative error is reduced greatly after the compensation is implemented, demonstrating the validity of the proposed compensation method.

Power conversion mechanisms for wave energy

Abstract: It is easy to make a device that will respond vigorously to the action of sea waves. Indeed, it is quite hard to make one that will not. However, the conversion of the slow, random, reversing energy flows with very high extreme values into phase-locked synchronous electricity with power quality acceptable to a utility network is very much harder. This paper describes a range of different control strategies of varying degrees of sophistication and then describes possible conversion equipment for high-pressure oil and water and low-pressure air. Like many renewable energy sources, waves would benefit from some form of energy storage, particularly if they are to be used in weak island networks. Flywheels, gas accumulators, submerged oil/vacuum accumulators, thermal stores and reversible fuel cells are discussed, with emphasis on the coupling hardware. This leads on to a description of a new type of hydraulic machine with digital control which has been specially designed for high efficiency and flexible contr...

Analysis of emerging technologies in the hydropower sector

Abstract: The paper reviews recent research and development activities in the field of hydropower technology. It covers emerging and advanced technologies to mitigate flow instabilities (active and passive a ...

Solar collector tracking system

Abstract: A solar collector tracking system that has a solar collection device having multiple lens assemblies mounted on its front surface. An exoskeleton structure is secured to the rear surface of the solar collection device and it is pivotally secured about a horizontal axis to the front end of an azimuth platform assembly. A hydraulic elevation actuator is pivotally mounted in the azimuth platform assembly about a horizontal axis and the front end of its piston rod is pivotally connected to the rear surface of the solar collection device and this allows it to be pivoted approximately 90 degrees between a vertical operating position and a horizontal storage position. The azimuth platform assembly is journaled on the top end of a tower extending up from the ground. A tubular post is rigidly secured to the top end of the post. A drive head extends horizontally from the tubular post and it has a pivot pin that extends upwardly therefrom. A primary and a secondary azimuth hydraulic actuator have the front ends of their respective piston rods coupled to the pivot pin. The opposite ends of the azimuth hydraulic actuators are pivotally secured to the interior of the azimuth platform assembly. A hydraulic power unit is connected to the respective hydraulic actuators. An electronic controller monitors signals from an azimuth encoder sensor and an elevation encoder sensor and it directs the respective hydraulic actuators to move their respective piston rods inwardly and outwardly so that the solar collection device can be rotated to track the rays of the sun.