High-Pressure Steam-Driven Jet Pump—Part II: Parametric Analysis

2000 ◽  
Vol 123 (3) ◽  
pp. 701-706 ◽  
Author(s):  
N. Beithou ◽  
H. S. Aybar
Keyword(s):  
Mathematical Modeling ◽  
Parametric Analysis ◽  
Cold Water ◽  
Water Pressure ◽  
Steam Pressure ◽  
Relative Difference ◽  
Inlet Pressure ◽  
Experimental Result ◽  
Jet Pump ◽  
Discharge Pressure

The steam-driven jet pump (SDJP) is a device without moving parts, in which steam is used as an energy source to pump cold water from a pressure much lower than the steam pressure to a pressure higher than the steam pressure. In the previous part of this study, the mathematical modeling of the SDJP has been done, and reported. The results of the mathematical modeling of the SDJP have been compared with Cattadori’s experimental results. The comparisons show that the experimental and calculated pressure distributions are in good qualitative agreement. For the same steam inlet pressure of 8.7 MPa, the discharge pressures in the experiment and in the simulation are 9.8 MPa and 9.54 MPa, respectively. The relative difference is two percent. It can be said that the computed discharge pressure is in good agreement with the experimental result. In the current study, a parametric analysis of the SDJP has been done in terms of four independent parameters: steam inlet pressure and temperature, supply water pressure, and temperature. The output parameters are: discharge pressure, temperature, and mass flow rate. As a result of this parametric study, the operation characteristics of the SDJP have been obtained.

High-Pressure Steam-Driven Jet Pump—Part I: Mathematical Modeling

2000 ◽  
Vol 123 (3) ◽  
pp. 693-700 ◽  
Author(s):  
N. Beithou ◽  
H. S. Aybar
Keyword(s):  
Mathematical Modeling ◽  
High Pressure ◽  
Cold Water ◽  
Cooling System ◽  
Steam Pressure ◽  
Good Qualitative Agreement ◽  
Jet Pump ◽  
Pressure Distributions ◽  
Pressure Steam ◽  
Core Cooling

There are several proposed advanced reactor systems, which consider the utilization of a steam-driven jet pump (SDJP) as an emergency core cooling system. The steam-driven jet pump is a device without moving parts, in which steam is used as an energy source to pump cold water from a pressure much lower than the steam pressure to a pressure higher than the steam pressure. In this study, the mathematical modeling of the SDJP has been done. An experimental analysis of the high-pressure SDJP has been reported by Cattadori et al. The results of the mathematical modeling of the SDJP have been compared with Cattadori’s experimental results. The comparisons show that the experimental and calculated pressure distributions are in good qualitative agreement. A parametric analysis of the SDJP is ongoing.

Mathematical modeling of a cryogenic jet pump with flows of different temperatures

1990 ◽  
Vol 26 (1) ◽  
pp. 18-22
Author(s):  
N. V. Filin ◽  
S. L. Simkhovich ◽  
I. F. Sultanov
Keyword(s):  
Mathematical Modeling ◽  
Jet Pump ◽  
Different Temperatures

Urinary responses to cold temperature during water immersion

1985 ◽  
Vol 248 (5) ◽  
pp. R560-R566 ◽  
Author(s):  
D. R. Knight ◽  
S. M. Horvath
Keyword(s):  
Sodium Excretion ◽  
Cold Water ◽  
Water Pressure ◽  
Water Immersion ◽  
Free Water ◽  
Cold Water Immersion ◽  
Cold Temperature ◽  
Ambient Water ◽  
Cold Temperatures ◽  
Diuretic Response

If cold temperature combines with ambient water pressure to stimulate the Henry-Gauer reflex in humans, then free water clearance (CH2O) should be greater during immersion in cold water (29.8 degrees C) than during exposure to cold air (14.8 degrees C) or immersion in thermoneutral water (35 degrees C). Urinary responses to these environments were compared with control measurements made during 6 h of sitting in thermoneutral air (27.6 degrees C). CH2O was not significantly greater in cold water than in the other environments. Rather, the diuretic response was characterized by an increased osmolar clearance (P less than 0.05). Cold temperature and water pressure additively raised urinary output during cold water immersion, with ambient water pressure accounting for two-thirds of the urinary water loss. An elevated rate of sodium excretion (P less than 0.05) began significantly earlier in cold water than in thermoneutral water. This effect of low temperature might have resulted from cold-induced vasoconstriction, since cold temperatures was observed to reduce the foot volume. Sodium excretion was inversely proportional to vital capacity, indicating a responsiveness of the kidney to expansion of the central blood volume. In addition to the effects of water pressure and cold temperature, urinary function was also sensitive to time. The rate of potassium excretion was significantly elevated at min 199 of exposure to all environments. Failure of CH2O to increase above control values indicated that the human diuretic response to cold water immersion is atypical for the Henry-Gauer reflex.

Subglacial water pressure records from a fast-flowing outlet glacier in Greenland

2020 ◽  
Author(s):  
Samuel Doyle ◽  
Bryn Hubbard ◽  
Poul Christoffersen ◽  
Marion Bougamont ◽  
Robert Law ◽  
...  
Keyword(s):  
Water Pressure ◽  
Drainage System ◽  
Greenland Ice Sheet ◽  
Distinct Component ◽  
Outlet Glacier ◽  
Diurnal Cycles ◽  
Close Proximity ◽  
Hydrological System ◽  
Discharge Pressure ◽  
Glacier Motion

<p>Glacier motion is resisted by basal traction that can be reduced significantly by pressurised water at the ice-bed interface. Few records of subglacial water pressure have been collected from fast-flowing, marine-terminating glaciers despite such glaciers accounting for approximately half of total ice discharge from the Greenland Ice Sheet.  The paucity of such measurements is due to the practical challenges in drilling and instrumenting boreholes to the bed, in areas that are often heavily-crevassed, through rapidly-deforming ice that ruptures sensor cables within weeks. Here, we present pressure records and drilling observations from two sites located 30 km from the calving front of Store Glacier in West Greenland, where ice flow averages ~600 m yr<sup>-1</sup>.  In 2018, boreholes were drilled 950 m to the bed near the margin of a large, rapidly-draining supraglacial lake. In 2019, multiple boreholes were drilled ~1030 m to the bed in the centre of the drained supraglacial lake, and in close proximity to a large, active moulin. All boreholes drained rapidly when they intersected or approached the ice-bed interface, which is commonly interpreted as indicating connection to an active subglacial drainage system. Neighbouring boreholes responded to the breakthrough of subsequent boreholes demonstrating hydrological or mechanical inter-connection over a distance of ~70 m. Differences in the time series of water pressure indicate that each borehole intersected a distinct component of the subglacial hydrological system. Boreholes located within 250 m of the moulin reveal clear diurnal cycles either in phase or anti-phase with moulin discharge. Pressure records from boreholes located on the lake margin, however, show smaller amplitude, and less distinct, diurnal cycles superimposed on longer-period (e.g. multiday) variability. We compare these datasets to those in the literature and investigate consistencies and inconsistencies with glacio-hydrological theory.</p>

scholarly journals Crack Detectability in Vertical Axis Cooling Pumps During Operation

2004 ◽  
Vol 10 (2) ◽  
pp. 121-133 ◽  
Author(s):  
N. Bachschmid ◽  
P. Pennacchi ◽  
E. Tanzi ◽  
P. Verrier ◽  
F. Hasnaoui ◽  
...  
Keyword(s):  
Cold Water ◽  
Water Pressure ◽  
Vertical Axis ◽  
Cyclic Stress ◽  
Hot Water ◽  
Rotating Shaft ◽  
Machine Condition Monitoring ◽  
Pump Shaft ◽  
Condition Monitoring System ◽  
Thermal Striping

The problem which is faced in this article is the analysis of the effects of a transverse propagating crack on the vibrational behavior of a vertical axis cooling pump. The crack is assumed to develop in a section between the impeller and a seal, preventing the hot water to flow upwards along the rotor shaft. The pressurized seal is fed with an injection of cold water, and crack initiation may be due to a thermal striping phenomenon. Afterwards, crack growth could be driven by a combination of thermal and mechanical loads, causing alternate cyclic stress in the shaft. Cracking instances of this type have been reported worldwide in several machines of similar design. In this article, the fact is emphasized that the crack behavior is likely to be influenced by the thermal field and by the water pressure in the cracked area. A dynamical lineshaft model, integrated by an original representation of the crack, has been developed to investigate the possible vibratory symptoms related to a crack propagation. The vibrations are generally measured in correspondence of a rigid coupling which connects the motor shaft to the pump shaft, in a position which is rather far away from the crack. 1 × rev., 2 × rev., and 3 × rev. vibration components, which are generally displayed by the machine condition monitoring system and are the most significative symptoms of the presence of a transverse crack in a rotating shaft, are calculated.

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