Hydraulic Energy Loss Research Articles

Studies on the Variation of Flow Parameters through a Ball Valve

This paper aims to highlight the current line of flow through a ball valve for opening its different angles. We chose to study the values of values 30o, 45o, 60o and 75o as represented in figures. Flow simulations were performed using Fluent 6.3 software, power lines are marked by their tangent vectors speed. For a default value of power flow and pressure were represented power lines following the turbulence and hence the increased loan losses occur. This ball valve operation analysis may reveal different hydraulic energy losses given conditions different valve opening and leads to a modern design and dynamic analysis of operation.

Multiobjective optimal design of runner blade using efficiency and draft tube pulsation criteria

In the present work new criteria of optimal design method for turbine runner [1] are proposed. Firstly, based on the efficient method which couples direct simulation of 3D turbulent flow and engineering semi empirical formulas, the combined method is built for hydraulic energy losses estimation in the whole turbine water passage and the efficiency criterion is formulated. Secondly, the criterion of dynamic loads minimization is developed for those caused by vortex rope precession downstream of the runner. This criterion is based on the finding that the monotonic increase of meridional velocity component in the direction to runner hub, downstream of its blades, provides for decreasing the intensity of vortex rope and thereafter, minimization of pressure pulsation amplitude. The developed algorithm was applied to optimal design of 640 MW Francis turbine runner. It can ensure high efficiency at best efficiency operating point as well as diminished pressure pulsations at full load regime.

The Research of Energy Saving Improved on Copper Anode in the Hydraulic System Based on AMESim

In response to the awareness of environmental conservation-oriented society and low carbon economy , this paper puts forwarding the load sensing control that is applied to the copper anode shaping machine hydraulic system energy transformation in the light of copper electrolytic anode shaping machine hydraulic system energy conservation issues, through the shaping machine hydraulic system energy loss analysis, and then uses AMESim software for plastic machine load sensing control system performance simulation and analysis, in order to achieve the purpose of energy saving.

Sound propagation in a pipe with dynamically rough boundary

The surface pattern of the water flow in partly filled circular pipe contains information on some key characteristics which are important for a better understanding of the hydraulic energy losses and turbulent processes. Surface pattern variation is a dynamic and nonstationary process which is difficult to measure directly. In this sense, airborne sound waves provide an attractive statistical mean which describes the apparent boundary roughness, its spatial correlation function, and frequency spectrum. These parameters can then be linked to key hydraulic characteristics of the flow. This work presents new experimental setup, which is used to study these characteristics under controlled laboratory conditions and allows for simultaneous measurements of the acoustic field in the pipe and water surface roughness. The acoustic technique makes use of Gaussian pulses which are transmitted in air above the turbulent flow of water over a carefully instrumented section and recorded on an intensity probe. The result...

Role of Energy Loss on Discharge Characteristics of Sluice Gates

A theoretical method was used to derive an equation for the discharge coefficient of sluice gates in rectangular channels under orifice-flow (both free and submerged) conditions. The proposed equation allows for the effects of energy dissipation between the upstream section of the gate and the vena contracta. The hydraulic energy loss in the upstream pool is attributable to the induced turbulence by the recirculating region and to the growth of bottom boundary layer. For the submerged-flow condition, turbulent shear-layer entrainment is also responsible for the energy loss. This energy loss is introduced into the equations through a coefficient k that has been conventionally assumed to be negligible. Experimental data from the literature were used to validate the equation, which showed good agreement with the measured values. It is also shown that the magnitude of the energy-loss factor is a function of the geometry of the gate and can modify the discharge coefficient. An equation for the distinguishing condition between free and submerged flows is also presented. The new equations can be used to predict the performance of sluice gates with different edge shapes under free- and submerged-flow situations.

Hydraulic Theory and Particle‐Driven Gravity Currents

Hydraulic theory, as it has been applied to compositionally driven gravity flows, involves the single simplifying assumption that the pressure in the fluid is hydrostatic [1]. This assumption provides, as a consequence, a depth independent horizontal velocity field. This approach has led to a greatly increased understanding of many of the phenomena associated with these complex flows, including issues surrounding internal hydraulic jumps and energy loss [2]. Recently, investigations into flow and deposition of particles from particle‐driven gravity currents have been carried out using an approach that employs the hydraulic theory that had proved so successful in the case of homogeneous flows [3]–[7]. Unfortunately, as we show here, there is a fundamental contradiction in adopting this simplifying assumption when particles drive the flow. This contradiction is essentially that one cannot have a hydrostatic pressure that arises from the presence of particles while at the same time maintaining a depth‐independent horizontal velocity field, as was assumed in references [3]–[7].

The effectiveness of terazosin, an alpha1-blocker, on bladder neck obstruction as assessed by urodynamic hydraulic energy.

To investigate the effectiveness of terazosin, an alpha1-adrenoceptor blocking agent, on bladder neck obstruction (BNO), by assessing the urodynamic hydraulic energy profile. Patients, subjects and methods The study included 17 men (mean age 60.1 years, range 24-84), comprising 11 patients with BNO (mean age 66.5 years) and six normal volunteers (mean age 48.1 years). A five-transducer microtip catheter was used to measure the pressure in the bladder and at the bladder neck, and in the membranous and bulbous urethra during voiding. All the subjects then received terazosin, 1 mg/day orally for 2 weeks, and were re-assessed. The bladder neck diameter at maximum flow significantly (P < 0.02) increased in the 11 patients with BNO after treatment with terazosin. The relative hydraulic energy profiles before terazosin treatment showed the greatest hydraulic energy loss between the membranous and the bulbous urethra in the normal subjects, and between the bladder neck and the membranous urethra in the men with BNO. After terazosin treatment, the greatest energy loss was between the membranous and the bulbous urethra in men with BNO, similar to that in the normal controls, i.e. the whole profile of relative hydraulic energy became normal. Terazosin was effective in opening the bladder neck and improving the hydraulic energy profile in men with BNO.

Draft Tube Performance of GAMM Francis Turbine.

Hydraulic energy loss in an elbow draft tube of GAMM Francis turbine is extracted from performance diagrams acquired in a normal model test which adopts a draft tube outlet as a low pressure measuring section, and in a special model test with a draft tube inlet section. An obtained diagram of draft tube energy loss versus discharge coefficient reveals that the loss is minimum at the two specific discharges, where the pertinent positive and negative swirls are supplied from the runner outflow to suppress the flow separation. The draft tube energy loss is maximum at a discharge between the two discharges above mentioned, where the flow at the runner outlet is free from swirl and induces the flow separation.