Unsteady flow in centrifugal pump at design and off design conditions

... of flow rates The unsteady numerical simulation at three different flow rates of 0.7Qdesign, Qdesign and 1.3Qdesign show that the inlet flow structure of straight intake section is flow rate ... exit into volute casing, the highly distorted radial flow, either at design or off -design condition causing unsteadiness flow in the volute casing The flow inside the volu...

Ngày tải lên: 10/09/2015, 08:27

Ngày tải lên: 13/11/2014, 10:12

... and M6 at pump design point The existence of back flow in the passages will increase the loss of the flow and thus reduce the efficiency of the centrifugal pump Some modification of the pump ... pressure side of blade surface The change of flow patterns at low flow rate is not obvious for model impellers M3 and M6, but it can still be seen that the recirculation...

Ngày tải lên: 16/09/2015, 17:14

... M5 Rotational speed (rpm) 2900 1 450 2900 1 450 2900 1 450 Design flow (m /h) 27 14 270 180 70 45 Design efficiency (%) 55 48 76 81 74 .5 65 Calculated efficiency (%) 58 .68 52 .5 79. 25 84.86 76 .5 ... size centrifugal pumps 82 Chapter Results and Discussions Table 5. 1 Specifications of model impellers Impeller Model M1 M2 M3 M4 M5 M6 Design speed 54 0 600 2900 1 450 2900...

Ngày tải lên: 16/09/2015, 17:14

... standard of our pump test stand This international standard is the first of a set dealing with acceptance tests of centrifugal, mixed flow and axial pumps; they correspond to three classes of tests ... each flow rate The performance test characteristics of design point are also recorded For example, to test the fourth model pump M4 at rotational speeds of 2900 rpm and 145...

Ngày tải lên: 16/09/2015, 17:14

... Ideal Gas Law: ρg = wp R0 T (3. 5) where w is the molecular weight of gas, and R0 is the Universal Gas constant Eqs (3. 1), (3. 2), (3. 3), (3. 4) and (3. 5) form a closed set of non-linear partial differential ... value σ =1 37 Chapter Theoretical Models of Two-Phase Flow 3. 4 Boundary Conditions The implementation of boundary conditions for multiphase flow is very similar to t...

Ngày tải lên: 16/09/2015, 17:14

... σ * =1 /2, σ =1 /2 22 Chapter Theoretical Models of Single-Phase Flow 2. 2.4 Shear Stress Transport (SST) Model While standard two-equation models provide good predictions for many flows of engineering ... (2. 9) and (2. 10) is the turbulent kinetic energy production term, which for incompressible flow is: Pk = µ t ∇U • (∇U + ∇U T ) (2. 11) Eqs (2. 1), (2. 2), (2. 9) and (2. 10) fo...

Ngày tải lên: 16/09/2015, 17:14

... the flows in centrifugal pump are three-dimensional turbulent flows, and a clear understanding of turbulent flow structures is essential for the optimization of the performance of centrifugal pumps ... volumetric flow and the total breakdown of the flow may occur when the gas fraction reaches about 8 -10 % of the total volumetric flow rate For two-phase flow applicat...

Ngày tải lên: 16/09/2015, 17:14

... Aims of the study The study aims at investigating the motivation in English speaking learning among the second year tourism- major students at Tourism and Foreign Language Faculty, Sao Do Industrial ... current situation of learning and teaching English speaking at Tourism and Foreign Language Department, Sao Do College...

Ngày tải lên: 07/11/2012, 15:01

... rib arrangements on heat transfer and flow behavior in a rectangular rib roughened passage” International Journal of Heat and mass transfer; 123: 675-681, 2001 [6] Lau S.C., McMillin R.D and Han ... studies of augmented heat transfer and friction in asymmetrically heated rectangular ducts with ribs on the heated wall in transverse, inclined, V-continu...

Ngày tải lên: 05/09/2013, 16:10

... over 40 years Initially, it was only a Vocational School Gradually, it was upgraded and became a Technical Teachers’ Training College in 1996, a Technical Teachers’ Training University in 2006 Now ... recognizing, understanding, comparing, and evaluating the information they encounter From all the opinions above it is clear that no definition can possibly capture a...

Ngày tải lên: 29/01/2014, 10:33

... containing mM EDTA The auto-oxidation rates of Asp40Ala and Asp40Asn mutants were measured at 25 °C Oxidation of the sample was observed by Ó FEBS 2004 Haem proximal side of a haem- regulated phosphodiesterase ... binding, redox potential and auto-oxidation rates of Ec DOS PAS, and catalytic activities of full-length enzymes We found that the mutations...

Ngày tải lên: 19/02/2014, 16:20

Ngày tải lên: 09/03/2014, 22:20