Cylindrical Storage Tanks Research Articles

Coupled vibration analysis of liquid-filled rigid cylindrical storage tank with an annular plate cover

An analytical approach is developed to investigate the vibration characteristics of the sloshing and bulging modes for a liquid-filled rigid circular cylindrical storage tank with an elastic annular plate in contact with sloshing surface of liquid. The cylindrical tank is filled with a non-viscous and incompressible liquid having a free surface. The free surface of liquid is partially covered by an annular plate with outer clamped edge and inner free edge. The liquid domain is limited by a rigid cylindrical wall and a rigid flat bottom. As the effect of free surface waves is taken into account in the analysis, the bulging and sloshing modes are studied. The solution for the velocity potential of liquid movement is assumed as a suitable harmonic function that satisfies the Laplace equation and the relevant boundary conditions. The Rayleigh–Ritz method is used to derive the frequency equation of the liquid-filled rigid cylindrical tank with an annular plate on the sloshing surface. The effects of inner-to-outer radius ratio, thickness of annular plate and liquid volume on vibration characteristics of the storage tank are studied. To demonstrate the validity of the present analytical approach, the published results are compared for the rigid cylindrical tank without a plate and the finite element analysis is performed for the tank with a plate.

Experimental investigation of thermal performance of a solar assisted heat pump system with an energy storage

An experimental solar assisted heat pump space heating system with a daily energy storage tank is designed and constructed, and its thermal performance is investigated. The heating system basically consists of flat plate solar collectors, a heat pump, a cylindrical storage tank, measuring units, and a heating room located in Gaziantep, Turkey (37.1°N). All measurements are automatically collected as a function of time by means of a measurement chain feeding to a data logger in combination with a PC. Hourly and daily variations of solar radiation, collector performance, coefficient of performance of the heat pump (COPHP), and that of the overall system (COPS) are calculated to evaluate the system performance. The effects of climatic conditions and certain operating parameters on the system performance parameters are investigated. COPHP is about 2.5 for a lower storage temperature at the end of a cloudy day and it is about 3.5 for a higher storage temperature at the end of a sunny day, and it fluctuates between these values in other times. Also, COPS turns out to be about 15–20% lower than COPHP. Copyright © 2004 John Wiley & Sons, Ltd.

737 薄肉円筒形貯水容器の液体との連成振動特性に関する実験的考察(定常流れのない場での非線形振動,OS-5:流体関連振動のメカニズムと計測制御(2))

A large amplitude excitation experiment was performed for a thin cylindrical water storage tanks in order to investigate the vibration characteristics. In addition to beam vibration, oval vibrations with the circumferential wave number n=12, 14 or 16 were observed. The acceleration level which generates an oval vibration was proportional to the increasing rate of magnitude of response acceleration of the tanks. It was found that one of generation mechanisms of the oval vibrations was a super summed and differential harmonic vibration having [l/2(p_1i+p_2 )] pattern.

04/00468 Investigation of thermal performance of a ground coupled heat pump system with a cylindrical energy storage tank: Yumrutas, R. et al. International Journal of Energy Research, 2003, 27, (11), 1051–1066.

04/00468 Investigation of thermal performance of a ground coupled heat pump system with a cylindrical energy storage tank: Yumrutas, R. et al. International Journal of Energy Research, 2003, 27, (11), 1051–1066.

Experimental study of CPC type ICS solar systems

Extensive experimental study on solar water heaters, which were developed in our laboratory, is presented. These solar devices are integrated collector storage (ICS) systems with single horizontal cylindrical storage tank properly placed in symmetric CPC type reflector trough. In this paper we study ICS solar systems, which differ in storage tank diameter and correlate their thermal performance and the ratios of the stored water volume per aperture area and also per total external surface area. Based on the results of this study and aiming to achieve improved ICS systems, we considered an effective tank diameter and we extracted by outdoor tests the performance of a number of experimental models differing in the absorbing surface, reflector and transparent cover. We calculated the mean daily efficiency and the thermal loss coefficient during night of each system combination. In addition, 24 h and four days operation diagrams of the variation of water temperature of the studied ICS systems are compared with the corresponding diagrams of two flat plate thermosiphonic units with mat black and selective absorbing surface, respectively. The experimental results show that ICS system with selective absorbing surface, high transmissivity of the transparent cover and high reflectance of its reflector surface performs efficiently enough, both during the day and night operation, approaching the thermal performance of the corresponding thermosiphonic unit of flat plate collector with selective absorber.

A study on thermal characteristics of the solar collector made with a closed loop thermosyphon

The natural circulation type and the closed loop type thermosyphon systems are widely used for solar domestic hot water systems(SDHWS). Of these, the closed loop type thermosyphon system, which hires the concept of a wickless heat pipe, is extensively studied in the present analysis. The system under consideration consists of a rectangular shape solar collector and a circular cylindrical shape storage tank, the most common design of a natural circulation type SDHWS. A closed circulation loop runs through these units carrying heat from the collector to the storage tank. The working fluid(heat transfer medium) makes infinite number of roundtrips via this loop as long as the sun's energy hit the collector area and delivers the fuel needed for the trip. This paper reports the experimental results obtained in a series of tests where the operational characteristics of various working fluids are examined along with the whole performance of the system. The working fluids experimented in the present study are ethanol, water, and a binary mixture of ethanol and water(ethanol/water). Various amounts of working fluid were tested where the working fluid occupies 30%, 40%, 50%, 60% or 70% of the loop volume. Among these, in the cases of 30% and 40%, dry-out phenomena were observed. Also investigated in this study were the flow patterns and the mechanism of heat transfer within the loop. Flow patterns of the binary mixture of working fluid near the entry of the storage tank were analyzed where they were recorded with the aid of a high speed camera.

Phase Change Energy Storage for Solar Heating Systems

In this study, the cylindrical phase change energy storage tank linked to the water source heat pump system is investigated theoretically and experimentally. A simulation model defining the transient behavior of the phase change unit was used. In the solar energy storage tank, the phase change material (PCM) is inside cylindrical plastic tubes and heat transfer fluid (water) flows parallel to it. The heat transfer problem of the PCM was solved numerically using an enthalpy-based finite differences method and was validated against the experimental data. The experiments were performed for clear days during the winter season in Trabzon, Turkey. In the experimental study, the mean temperature of the water and the temperature distribution of the PCM in the tank were measured. The inlet and outlet water temperature of the tank and the inlet and outlet temperature of the solar collectors and the water-source heat pump are also measured. The experimentally obtained inlet and outlet water temperatures are also taken as inlet/outlet water temperatures in the simulation model. Thus the theoretical temperature and stored heat energy distribution in the energy storage tank have been determined by using a computer program developed previously. In this study, solar radiation on horizontal and tilted surfaces in Trabzon are also measured and calculated while the collector and storage efficiencies have been calculated. The theoretical results were found to be in good agreement with the experimental values.

Phase Change Energy Storage for Solar Heating Systems

In this study, the cylindrical phase change energy storage tank linked to the water source heat pump system is investigated theoretically and experimentally. A simulation model defining the transient behavior of the phase change unit was used. In the solar energy storage tank, the phase change material (PCM) is inside cylindrical plastic tubes and heat transfer fluid (water) flows parallel to it. The heat transfer problem of the PCM was solved numerically using an enthalpy-based finite differences method and was validated against the experimental data. The experiments were performed for clear days during the winter season in Trabzon, Turkey. In the experimental study, the mean temperature of the water and the temperature distribution of the PCM in the tank were measured. The inlet and outlet water temperature of the tank and the inlet and outlet temperature of the solar collectors and the water-source heat pump are also measured. The experimentally obtained inlet and outlet water temperatures are also taken as inlet/outlet water temperatures in the simulation model. Thus the theoretical temperature and stored heat energy distribution in the energy storage tank have been determined by using a computer program developed previously. In this study, solar radiation on horizontal and tilted surfaces in Trabzon are also measured and calculated while the collector and storage efficiencies have been calculated. The theoretical results were found to be in good agreement with the experimental values.

Integrated collector storage solar systems with asymmetric CPC reflectors

New types of ICS solar systems were designed and outdoor tests of experimental models were performed. The systems consist of single cylindrical horizontal water storage tanks placed inside stationary truncated asymmetric CPC reflector troughs of different design. We used high emittance absorber surface, low cost curved reflectors, iron oxide glazing and thermal insulation at the non illuminated tank surfaces, aiming towards cost effective ICS systems with satisfactory heat preservation during the night. Four experimental models of different designs were constructed and tested to determine their performance regarding their mean daily efficiency and thermal losses during the night. The new ICS systems were compared to an ICS system with symmetric CPC reflectors of similar construction and dimensions and also to a typical Flat Plate Thermosiphonic Unit (FPTU). Test results showed that the ICS systems with asymmetric CPC reflectors present almost the same mean daily efficiency and better preservation of hot water temperature during the night, compared to the ICS system with the symmetric CPC reflectors. The comparison with the FPTU system confirmed the satisfied daily operation of all ICS systems and their moderate storage heat preservation during the night. Theoretical results showed acceptable thermal performance of all ICS systems regarding annual operation.

ICS solar systems with horizontal cylindrical storage tank and reflector of CPC or involute geometry

The use of a horizontal cylindrical water storage tank contributes to pressure resistant, low height and efficient ICS solar systems. These systems can satisfactorily achieve water heating when the cylindrical storage tank is combined with stationary CPC or involute type curved reflectors. The diameter of the cylindrical storage tank determines the length of the reflectors, the system depth and the ratio of the stored water per aperture area. In these solar systems the storage tank can be partially thermally insulated to suppress thermal losses from it to the ambience. We constructed four experimental models with truncated symmetric CPC reflectors, two with 90° and other two with 60° of acceptance angle, half of them without and half with a 1/4 thermally insulated storage tank cylindrical surface. In addition, we constructed two ICS systems with involute reflectors, with acceptance angle 180°, one without and the other one with a 1/4 thermally insulated storage tank. The six ICS systems were tested under the same weather conditions and without water drain, to determine their stored water temperature variation, mean daily efficiency and thermal losses during night. The results showed that CPC reflectors contribute to efficient operation of systems day and night, while involute reflectors mainly to the water heat preservation during night.

ICS solar systems with horizontal (E–W) and vertical (N–S) cylindrical water storage tank

Cylindrical type storage tanks are used in most commercial ICS systems, as they resist to the pressure of water mains. ICS systems with one or two cylindrical storage tanks combined with curved reflectors are cost effective devices and can be easily used in domestic solar applications. In this paper we compare ICS solar systems with cylindrical water storage tank and different mountings of it in a symmetric CPC or involute reflector trough. The design, construction and experimental results from four ICS systems regarding water temperature profile, mean daily efficiency and thermal losses during night are presented and discussed. The experimental models are tested outdoors under the same weather conditions and without water drainage for a sequence of 3 days, starting the first day with cold water. During tests we have recorded solar radiation, ambient temperature, water temperature in different locations inside the storage tank and also wind speed. The results show that during the day the ICS systems with a horizontal tank present a satisfactory performance in water temperature rise and heat preservation in water storage tank during night. Regarding reflector types, the ICS models with CPC reflectors achieve higher mean daily efficiency, while models with involute reflectors present high efficiency only in low operating temperatures.

A polymer electrolyte membrane fuel cell system for powering portable computers

The Fraunhofer Institute for Solar Energy Systems ISE has developed a fuel cell system to power a portable computer. The components are a four-cell polymer electrolyte membrane fuel cell (PEMFC) system, a six-phase DC/DC-converter, an air pump, two cylindrical metal hydride storage tanks, a valve and a pressure sensor to adjust the hydrogen flow [national patent applied, DE 101 19 339, 03 (2001)] and a control unit for the management of the whole system. Prominent characteristics of the system are a flat design of the fuel cell stack and the integrated DC/DC-converter [national patent granted, DE 198 10 556 C1, 11 (1999)]. The system provides a nominal power output of about 42 W at 12 V. Extensive physical investigations of different flow field combinations as well as the system design are presented.

Investigation of thermal performance of a ground coupled heat pump system with a cylindrical energy storage tank

An analytical and computational model for a solar assisted heat pump heating system with an underground seasonal cylindrical storage tank is developed. The heating system consists of flat plate solar collectors, an underground cylindrical storage tank, a heat pump and a house to be heated during winter season. Analytical solution of transient field problem outside the storage tank is obtained by the application of complex finite Fourier transform and finite integral transform techniques. Three expressions for the heat pump, space heat requirement during the winter season and available solar energy are coupled with the solution of the transient temperature field problem. The analytical solution presented can be utilized to determine the annual variation of water temperature in the cylindrical store, transient earth temperature field surrounding the store and annual periodic performance of the heating system. A computer simulation program is developed to evaluate the annual periodic water and earth temperatures and system performance parameters based on the analytical solution. Copyright © 2003 John Wiley & Sons, Ltd.

351 繊維強化複合材で補強された円筒タンクの自由振動解析

351 繊維強化複合材で補強された円筒タンクの自由振動解析

Flow and dispersion around storage tanks -A comparison between numerical and wind tunnel simulations

Accidental gaseous losses from industrial processes can pose considerable health and environmental risks but assessing their health, safety and environmental impact is problematic. Improved understanding and simulation of the dispersion of emissions in the vicinity of storage tanks is required. The present study aims to assess the capability of the turbulence closures and meshing alternatives in a commercially available CFD code for predicting dispersion in the vicinity of cubes and circular cylindrical storage tanks. The performance of the <TEX>$k-{\varepsilon}$</TEX> and Reynolds Stress turbulence models and meshing alternatives for these cases are compared to experimental data. The CFD simulations are very good qualitatively and, in many cases, quantitatively. A mesh with prismatic elements is more accurate than a tetrahedral mesh. Overall the Reynolds stress model performs slightly better than the <TEX>$k-{\varepsilon}$</TEX> model.

CPC type integrated collector storage systems

Integrated collector storage (ICS) solar water heaters with stationary compound parabolic concentrating (CPC) reflectors are designed and test results are presented. The systems consist of single and double cylindrical horizontal tanks properly placed in truncated symmetric and asymmetric CPC reflector troughs. The suggested designs aim to achieve low cost systems with improved performance by the reduction of their thermal losses and the increase of water temperature rise by using the non-uniform distribution of solar radiation on the absorber surface. Four experimental models were constructed and tested outdoors to determine their mean daily efficiency and thermal losses during the night. Test results showed that asymmetric CPC reflectors contribute to lower thermal losses and the two connected in series cylindrical storage tanks result in effective water temperature stratification. The system with the single cylindrical storage tank and the symmetric CPC reflector performs satisfactorily during the day as well as during the night and regarding its simpler design it could be considered cost effective among the studied ICS systems. A typical thermosiphonic system with flat plate collector was tested for performance comparison, by which the improved daily efficiency of ICS systems and also their moderate water storage heat preservation during the night were confirmed.

123 鉛直加振を受ける円筒型 FRP 製貯槽の応答解析と実験

123 鉛直加振を受ける円筒型 FRP 製貯槽の応答解析と実験

Nonlinear Analysis on Rocking and Sliding Coupled Response of Cylindrical Tank Due to Seismic Excitation.

The effect of rocking motion of the anchored and unanchored flexible cylindrical storage tanks on sliding response due to the seismic excitation is investigated. The five-degree of freedom model is developed in order to examine the seismic response of them. This model is able to take account of the coupling behavior between sliding and rocking, the flexible deformation of the shell and base plate. The validity of the presented mechanical model is demonstrated by the shaking table experiments with large and small model tanks. It is clarified that the taller tank is easier to slide than the broader ones by simulation results obtained by parametric study for actual size tanks.

Dipsticks for Cylindrical Storage Tanks—Exact and Approximate

David Sanchez (dsanchez@math.tamu.edu) did his undergraduate studies at the University of New Mexico and received his Ph.D. from the University of Michigan. He has been a professor of mathematics at UCLA and the University of New Mexico. His major field of research is ordinary differential equations. For nine years he acquired a severe case of administrativitis, but recovered and is happily teaching at Texas A&M University.

Seismic isolation of rigid cylindrical tanks using friction pendulum bearings

AbstractStorage tanks are vulnerable to earthquakes, as numerous major earthquakes have demonstrated. The trend of recent revisions to make seismic design criteria for large‐scale industrial storage tanks increasingly stringent has made development of cost‐effective earthquake‐resistant design and retrofit techniques for industrial tanks imperative. This study assesses the feasibility of seismic base isolation for making liquid‐filled storage tanks earthquake resistant. The sliding‐type friction pendulum seismic (FPS) bearings are considered rather than the elastomeric bearings because the dynamic characteristics of an FPS‐isolated tank remain unchanged regardless of the storage level. This work has devised a hybrid structural‐hydrodynamic model and solution algorithm, which would permit simple, accurate and efficient assessment of the seismic response of rigid cylindrical storage tanks in the context of seismic isolation. Extensive numerical simulations confirm the effectiveness of seismic base isolation of rigid cylindrical tanks using FPS bearings. Copyright © 2001 John Wiley &amp; Sons, Ltd.