Simulating Design Storms with Water Chamber Testing

Author(s):  
CL Galitz ◽  
AR Whitlock
Keyword(s):  
Author(s):  
Neander Berto Mendes ◽  
Lineu José Pedroso ◽  
Paulo Marcelo Vieira Ribeiro

ABSTRACT: This work presents the dynamic response of a lock subjected to the horizontal S0E component of the El Centro earthquake for empty and completely filled water chamber cases, by coupled fluid-structure analysis. Initially, the lock was studied by approximation, considering it similar to the case of a double piston coupled to a two-dimensional acoustic cavity (tank), representing a simplified analytical model of the fluid-structure problem. This analytical formulation can be compared with numerical results, in order to qualify the responses of the ultimate problem to be investigated. In all the analyses performed, modeling and numerical simulations were done using the finite element method (FEM), supported by the commercial software ANSYS.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.


2021 ◽  
Vol 13 (4) ◽  
pp. 290-295
Author(s):  
E. A. Sukhorukova ◽  
N. N. Trifonov ◽  
S. P. Kolpakov

In the thermal circuits of domestic steam turbines, mixing-type low-pressure heaters (LPH) with free-flow jet water distribution and counter-flow of water and steam are widely used. The choice of the counterflow variant of the media movement ensures the most efficient heat transfer. However, the technical problem of ensuring reliable operation of LPH in the entire range of design loads of TPP and NPP power units is still relevant.During the commissioning and operation of mixing-type LPH in 800÷1200 MW turbines of TPP and NPP, the presence of metal knocks in the zone of the check valve, hydraulic shocks in the heating section were revealed. A priori, these phenomena indicated design flaws in LPH or manufacturing defects in their production. Research carried out by NPO CKTI specialists showed that periodic hydraulic shocks in the heating section and metal knocks occur as a result of uneven distribution around the circumference of the main condensate and steam supply. This leads to a breakdown of the check valve and the destruction of perforated plates and off-design heating of water in the volume of the annular LPH water chamber. To clarify the causes of the damage, develop recommendations for the reconstruction of the apparatus and further account for the design, two series of experimental studies were carried out on mixing-type heaters of 800 MW turbine units PNSV-2000-1 and PNSV-2000-2 manufactured at PJSC Krasny Kotelshchik. The purpose of the experimental studies was to determine the change in the water level in the water chamber and the heating of the main condensate in the elements of the heating compartment during normal operation of the power unit at loads of 400÷850 MW. Based on the results of the research, the method for calculating the mixing-type LPH has been refined, taking into account the revealed non-uniformity of water heating in the water chamber, recommendations for their reconstruction have been developed and implemented. 


Author(s):  
Jun MITSUI ◽  
Mikihisa WATANABE ◽  
Shin-ichi KUBOTA ◽  
Akira MATSUMOTO

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A374-A375
Author(s):  
K K Pruss ◽  
D Willis ◽  
B J Spray ◽  
S Jambhekar

Abstract Introduction The Sleep Clinic at Arkansas Children’s follows approximately 300 children who require positive airway pressure (PAP) at home. The clinic respiratory therapist provides oral and written cleaning instructions while some physicians choose to provide their own instructions. The home equipment company who supplies PAP in the home also gives cleaning instructions. The different routes of information given may result in inconsistent practices. It is extremely important to clean PAP equipment as directed as infection and illness may result from improper cleaning. Methods Caregivers of children who utilize home PAP devices were invited to complete an anonymous survey regarding cleaning practices during a Sleep clinic appointment. Data were collected electronically. Descriptive statistics were utilized to summarize results. Results There were 96 participants of whom 90% (87/96) were parents/caregivers. The mean age of the equipment user was 12 years and most were male (69%, 66/96). The mean length of time the equipment had been used was 2.6 years (SD 3.2). The majority of respondents, 67% (64/95), identified the parent/caregiver as responsible for cleaning. Only 25% (24/96) reported cleaning the mask daily as recommended; 43% (41/96) of participants reported cleaning tubing weekly; 27% (26/96) reported cleaning the water chamber daily by while most reported at least weekly (47%, 45/96). The majority, 58% (56/96) reported emptying the water chamber daily and using distilled water (81%, 74/96). Most respondents did not note respiratory symptoms starting/increasing with PAP (67%, 64/96). Of those with respiratory symptoms attributed to PAP, congestion was the most common (79%, 11/14). Conclusion There is a discrepancy between recommended and actual practices for cleaning PAP equipment. No significant association was found between the duration of PAP use and cleaning practices. However, a moderately low correlation between age and cleaning was identified. Increased age was associated with decreased cleaning practices. Support  


2014 ◽  
Vol 621 ◽  
pp. 294-303
Author(s):  
Feng He Wu ◽  
Shu Zhi Li ◽  
Chong Min Jiang ◽  
Dong Dong Gao

As the key part of nuclear pressure vessels, the water chamber head has the features of large size, complex shape and difficult processability. The processes of conventional machining method are too decentralized, the cumulative error is large, and the processing cycle is long. In order to meet the efficiency and high-precision machining requirements of the nuclear power water chamber head, a design scheme of special turn-milling machining center and B-axis components is proposed. The part characteristics and machining difficulties of the water chamber head are analyzed in the paper. The machining areas and processes are subdivided, the numerical control technological process is presented. In order to complete the finish machining of the water chamber's inner and outer surfaces and its inclined holes and sloping faces, the movable gantry milling machining center with pendulant ram is designed. According to the head processing requirements, three design schemes of B-axis components assembly, single row cylindrical roller bearing type, double row tapered roller bearing type and the central axis unloading type, are proposed. Through the theory analysis and statics and modal comparative analysis, the central axis unloading type is adopted as the optimal proposal in B-axis component design. Simulation and experimental results show that the turn-milling machining center based on the unloading B-axis assembly can satisfy the precision requirement of the water chamber head.


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