Volute Pressure Distribution, Radial Force on the Impeller, and Volute Mixing Losses of a Radial Flow Centrifugal Pump

1960 ◽  
Vol 82 (2) ◽  
pp. 136-143 ◽  
Author(s):  
H. W. Iversen ◽  
R. E. Rolling ◽  
J. J. Carlson
Keyword(s):  
Pressure Distribution ◽  
Centrifugal Pump ◽  
Radial Flow ◽  
Radial Force ◽  
Distribution Analysis ◽  
Pressure Distributions ◽  
Hydraulic Conditions ◽  
Pump Head ◽  
Capacity Performance ◽  
Mixing Losses

A standard volute-type, radial-flow, centrifugal pump was instrumented to obtain the pressure distribution in the volute and also the bearing reactions from the pump hydraulic force transmitted to the shaft. The resultant force from the integrated pressure distribution was found to give a reasonable design approximation of the radial force. An analysis of hydraulic conditions within the volute gave pressure distributions and radial-force magnitudes that were comparable to those measured with certain qualitative interpretations about internal recirculations. In addition, the pressure-distribution analysis furnished an interpretation of the effect of the volute on the pump head-capacity performance with corrections to the impeller head. The predicted head-capacity relationship had the form of the measured pump performance.

scholarly journals Numerical Investigation on the Mechanism of Double-Volute Balancing Radial Hydraulic Force on the Centrifugal Pump

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 689
Author(s):  
Yuan ◽  
Yuan ◽  
Tang
Keyword(s):  
Centrifugal Pump ◽  
Cross Sections ◽  
Performance Test ◽  
Flow Characteristics ◽  
Radial Force ◽  
Transient Pressure ◽  
Force Magnitude ◽  
Hydraulic Force ◽  
Pump Head ◽  
Cfd Method

Double-volute is an effective technique to reduce radial hydraulic force on the centrifugal pump and thereby mitigate the pump-casing vibration induced by unsteady flow characteristics. The mechanism of the double-volute structure balancing radial force on the impeller and volute was investigated on the basis of volute cross-sections by using Computational Fluid Dynamics (CFD) method. The tested performances and simulated inner-flow characteristics of two pumps with single-volute and double-volute were compared in this paper. The performance-test results verify the veracity of CFD method and illustrate that double-volute pump has some losses in terms of pump head and operation efficiency. The numerical simulations reveal that double-volute pump has smaller radial-force magnitude than single-volute pump on the abnormal conditions. Steady pressure field and transient pressure variations of pumps were explored to account for radial-force characteristics of double-volute pump. Compared with the single-volute structure, obvious pressure increases were found in the upper chamber (single part) of the double-volute, while the static pressure decreased in the lower chamber (double chambers). This situation reduces the pressure difference between two volute cross-sections in the collinear radial direction, resulting in smaller radial hydraulic force. Moreover, the transient simulations present the same phenomenon. The radial-forces distribute more uniformly in the double-volute pump, which can alleviate some vibrations.

Pressure Distribution under Symptom-Free Feet during Barefoot Standing

Foot & Ankle ◽  
1987 ◽  
Vol 7 (5) ◽  
pp. 262-278 ◽  
Author(s):  
Peter R. Cavanagh ◽  
Mary M. Rodgers ◽  
Akira liboshi
Keyword(s):  
Body Weight ◽  
Pressure Distribution ◽  
Significant Relationship ◽  
Plantar Pressure ◽  
Load Distribution ◽  
Peak Pressure ◽  
Distribution Analysis ◽  
Pressure Distributions ◽  
Transverse Arch ◽  
Peak Pressures

The plantar pressure distributions for a large heterogeneous sample of feet (N = 107) were collected during barefoot standing using a capacitance mat. From these data, the function of the foot during standing was characterized. Peak pressures under the heel (139 kPa) were, on average, 2.6 times greater than forefoot pressures (53 kPa). Forefoot peak pressures were usually located under the second or third metatarsal heads. No significant relationship was found between body weight and the magnitude of peak pressure. The concepts of a transverse arch at the level of the metatarsal heads and a “tripod” theory of load distribution were not substantiated by this study. Load distribution analysis showed that the heel carried 60%, the midfoot 8%, and the forefoot 28% of the weightbearing load. The toes were only minimally involved in the weightbearing process. Examples of unusual distributions are shown; finally, a checklist is provided to aid the clinician in evaluating plantar pressure findings.

Pressure Distribution Along the Casing of a Centrifugal Pump and Its Effect on Support Bearing Temperature Distribution

2004 ◽  
Author(s):  
Bhupendra K. Gandhi ◽  
Sanjeev Bharani
Keyword(s):  
Temperature Distribution ◽  
Pressure Distribution ◽  
Centrifugal Pump ◽  
Radial Force ◽  
Transfer Energy ◽  
Pump Impeller ◽  
Small Eccentricity ◽  
Delivery Pressure ◽  
Centrifugal Pump Impeller ◽  
Made In

In a centrifugal pump, impeller transfer energy to liquids and a part of the transferred kinetic energy converts into the pressure energy in the surrounding casing. Any asymmetric pressure distribution around the impeller gives rise to radial force, which increases temperature at support bearings of the pump. An effort has been made in the present work to relate rise in the bearing temperature with the pressure distribution around the impeller with and without minor change in its position (by 0.5–1.0 mm) relative to the casing. The maximum bearing temperature is found at full open delivery valve (low delivery pressure). It has been observed that the reduction in asymmetric pressure distribution reduces the bearing temperature rise to the order of 10°C. It is seen that a small eccentricity of 1.0 mm in the position of impeller with respect to the volute casing gives less asymmetric pressure distribution at the low delivery pressure where as at high delivery pressures, it results in higher asymmetric pressure distribution compare to the concentric mounting of the impeller.

Life Evaluation of a Disk Brake of Railway Vehicles Considering Pressure Distributions at a Frictional Surface

2007 ◽  
Vol 353-358 ◽  
pp. 303-306 ◽  
Author(s):  
Sung Keun Cho ◽  
Jung Hun Choi ◽  
Young Min Lee ◽  
Chang Sung Seok
Keyword(s):  
Thermal Stress ◽  
Pressure Distribution ◽  
Contact Surface ◽  
3D Model ◽  
Thermal Stresses ◽  
Distribution Analysis ◽  
Disk Brake ◽  
Pressure Distributions ◽  
Life Evaluation ◽  
Stress Analyses

In this study, we performed thermal stress analyses on a ventilated disk brake with a 3D model for two cases (whether the pressure distribution on a contact surface is uniform or not). A pressure distribution analysis was performed to determine the pressure distribution on the contact surface. Then, by using the results that were obtained from the pressure distribution analyses, we performed thermal stress analyses. Finally, we have found the spots where the maximum thermal stresses occur. Also, for the life evaluation of a disk brake, we have conducted the fatigue test and obtained the S-N curve. From those results, we evaluated the life of a disk brake.

Effect of semi-open impeller side clearance on centrifugal pump cavitation inception

2018 ◽  
Vol 1 (2) ◽  
pp. 24-39
Author(s):  
A. Farid ◽  
A. Abou El-Azm Aly ◽  
H. Abdallah
Keyword(s):  
Centrifugal Pump ◽  
Static Pressure ◽  
Rotation Speed ◽  
Centrifugal Pumps ◽  
Severe Condition ◽  
Cavitation Inception ◽  
Total Input ◽  
Input Pressure ◽  
Pump Head ◽  
Pump Pressure

Cavitation in pumps is the most severe condition that centrifugal pumps can work in and is leading to a loss in their performance.  Herein, the effect of semi-open centrifugal pump side clearance on the inception of pump cavitation has been investigated.  The input pump pressure has been changed from 80 to 16 kPa and the pump side clearance has been changed from 1 mm to 3 mm at a rotation speed of 1500 rpm. It has been shown that as the total input pressure decreased; the static pressure inside the impeller is reduced while the total pressure in streamwise direction has been reduced, also the pump head is constant with the reduction of the total input pressure until the cavitation is reached. Head is reduced due to cavitation inception; the head is reduced in the case of a closed impeller with a percent of 1.5% while it is reduced with a percent of 0.5% for pump side clearance of 1mm, both are at a pressure of 20 kPa.   Results also showed that the cavitation inception in the pump had been affected and delayed with the increase of the pump side clearance; the cavitation has been noticed to occur at approximate pressures of 20 kPa for side clearance of 1mm, 18 kPa for side clearances of 2mm and 16 kPa for 3mm.

scholarly journals Effect of Pressure Distribution on the Energy Dissipation of Lap Joints under Equal Pre-tension Force

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 320-328
Author(s):  
Delin Sun ◽  
Minggao Zhu
Keyword(s):  
Energy Dissipation ◽  
Pressure Distribution ◽  
Theoretical Basis ◽  
Lap Joints ◽  
Power Exponent ◽  
Lap Joint ◽  
Stick Slip ◽  
Pressure Distributions ◽  
Hysteretic Characteristics ◽  
Effective Use

Abstract In this paper, the energy dissipation in a bolted lap joint is studied using a continuum microslip model. Five contact pressure distributions compliant with the power law are considered, and all of them have equal pretension forces. The effects of different pressure distributions on the interface stick-slip transitions and hysteretic characteristics are presented. The calculation formulation of the energy dissipation is introduced. The energy dissipation results are plotted on linear and log-log coordinates to investigate the effect of the pressure distribution on the energy distribution. It is shown that the energy dissipations of the lap joints are related to the minimum pressure in the overlapped area, the size of the contact area and the value of the power exponent. The work provides a theoretical basis for further effective use of the joint energy dissipation.

scholarly journals Dynamic flight load measurements with MEMS pressure sensors

2021 ◽  
Author(s):  
Christian Raab ◽  
Kai Rohde-Brandenburger
Keyword(s):  
Pressure Distribution ◽  
Pressure Sensors ◽  
Flow Characteristics ◽  
Flight Test ◽  
Measurement Technology ◽  
Test Program ◽  
Aerodynamic Pressure ◽  
Pressure Distributions ◽  
Time Histories ◽  
Mems Pressure Sensors

AbstractThe determination of structural loads plays an important role in the certification process of new aircraft. Strain gauges are usually used to measure and monitor the structural loads encountered during the flight test program. However, a time-consuming wiring and calibration process is required to determine the forces and moments from the measured strains. Sensors based on MEMS provide an alternative way to determine loads from the measured aerodynamic pressure distribution around the structural component. Flight tests were performed with a research glider aircraft to investigate the flight loads determined with the strain based and the pressure based measurement technology. A wing glove equipped with 64 MEMS pressure sensors was developed for measuring the pressure distribution around a selected wing section. The wing shear force determined with both load determination methods were compared to each other. Several flight maneuvers with varying loads were performed during the flight test program. This paper concentrates on the evaluation of dynamic flight maneuvers including Stalls and Pull-Up Push-Over maneuvers. The effects of changes in the aerodynamic flow characteristics during the maneuver could be detected directly with the pressure sensors based on MEMS. Time histories of the measured pressure distributions and the wing shear forces are presented and discussed.

scholarly journals Influence of the Spatial Pressure Distribution of Breaking Wave Loading on the Dynamic Response of Wolf Rock Lighthouse

2021 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
Darshana T. Dassanayake ◽  
Alessandro Antonini ◽  
Athanasios Pappas ◽  
Alison Raby ◽  
James Mark William Brownjohn ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Pressure Distribution ◽  
Distinct Element ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Loading ◽  
Wave Impact ◽  
Pressure Distributions ◽  
Impact Area ◽  
The Impact

The survivability analysis of offshore rock lighthouses requires several assumptions of the pressure distribution due to the breaking wave loading (Raby et al. (2019), Antonini et al. (2019). Due to the peculiar bathymetries and topographies of rock pinnacles, there is no dedicated formula to properly quantify the loads induced by the breaking waves on offshore rock lighthouses. Wienke’s formula (Wienke and Oumeraci (2005) was used in this study to estimate the loads, even though it was not derived for breaking waves on offshore rock lighthouses, but rather for the breaking wave loading on offshore monopiles. However, a thorough sensitivity analysis of the effects of the assumed pressure distribution has never been performed. In this paper, by means of the Wolf Rock lighthouse distinct element model, we quantified the influence of the pressure distributions on the dynamic response of the lighthouse structure. Different pressure distributions were tested, while keeping the initial wave impact area and pressure integrated force unchanged, in order to quantify the effect of different pressure distribution patterns. The pressure distributions considered in this paper showed subtle differences in the overall dynamic structure responses; however, pressure distribution #3, based on published experimental data such as Tanimoto et al. (1986) and Zhou et al. (1991) gave the largest displacements. This scenario has a triangular pressure distribution with a peak at the centroid of the impact area, which then linearly decreases to zero at the top and bottom boundaries of the impact area. The azimuthal horizontal distribution was adopted from Wienke and Oumeraci’s work (2005). The main findings of this study will be of interest not only for the assessment of rock lighthouses but also for all the cylindrical structures built on rock pinnacles or rocky coastlines (with steep foreshore slopes) and exposed to harsh breaking wave loading.

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