Tank Wall

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A Oliva - One of the best experts on this subject based on the ideXlab platform.

  • thermo mechanical parametric analysis of packed bed thermocline energy storage Tanks
    2016
    Co-Authors: I Gonzalez, C D Perezsegarra, O Lehmkuhl, S Torras, A Oliva
    Abstract:

    A packed-bed thermocline Tank represents a proved cheaper thermal energy storage for concentrated solar power plants compared with the commonly-built two-Tank system. However, its implementation has been stopped mainly due to the vessel’s thermal ratcheting concern, which would compromise its structural integrity. In order to have a better understanding of the commercial viability of thermocline approach, regarding energetic effectiveness and structural reliability, a new numerical simulation platform has been developed. The model dynamically solves and couples all the significant components of the subsystem, being able to evaluate its thermal and mechanical response over plant normal operation. The filler material is considered as a cohesionless bulk solid with thermal expansion. For the stresses on the Tank Wall the general thermoelastic theory is used. First, the numerical model is validated with the Solar One thermocline case, and then a parametric analysis is carried out by settling this storage technology in two real plants with a temperature rise of 100°C and 275°C. The numerical results show a better storage performance together with the lowest temperature difference, but both options achieve suitable structural factors of safety with a proper design.

Zhan Liu - One of the best experts on this subject based on the ideXlab platform.

  • fluid thermal stratification in a non isothermal liquid hydrogen Tank under sloshing excitation
    2018
    Co-Authors: Zhan Liu, Yuyang Feng, Gang Lei
    Abstract:

    Abstract To the safe space operation of cryogenic storage Tank, it is significant to study fluid thermal stratification under external heat leaks. In the present paper, a numerical model is established to investigate the thermal performance in a cryogenic liquid hydrogen Tank under sloshing excitation. The interface phase change and the external convection heat transfer are considered. To realize fluid sloshing, the dynamic mesh coupled the volume of fluid (VOF) method is used to predict the interface fluctuations. A sinusoidal excitation is implemented via customized user-defined function (UDF) and applied on Tank Wall. The grid sensitivity study and the experimental validation of the numerical mode are made. It turns out that the present numerical model can be used to simulate the unsteady process in a non-isothermal sloshing Tank. Variations of Tank pressure, liquid and vapor mass, fluid temperature and thermal stratification are numerically investigated respectively. The results show that the sinusoidal excitation has caused large influence on thermal performance in liquid hydrogen Tank. Some valuable conclusions are arrived, which is important to the depth understanding of the non-isothermal performance in a sloshing liquid hydrogen Tank and may supply some technique reference for the methods of sloshing suppression.

  • influence of slosh baffles on thermodynamic performance in liquid hydrogen Tank
    2018
    Co-Authors: Zhan Liu
    Abstract:

    Abstract A calibrated CFD model is built to investigate the influence of slosh baffles on the pressurization performance in liquid hydrogen (LH2) Tank. The calibrated CFD model is proven to have great predictive ability by compared against the flight experimental results. The pressure increase, thermal stratification and Wall heat transfer coefficient of LH2 Tank have been detailedly studied. The results indicate that slosh baffles have a great influence on Tank pressure increase, fluid temperature distribution and Wall heat transfer. Owning to the existence of baffles, the stratification thickness increases gradually with the distance from Tank axis to Tank Wall. While for the Tank without baffles, the stratification thickness decreases firstly and then increases with the increase of the distance from the axis. The “M” type stratified thickness distribution presents in Tank without baffles. One modified heat transfer coefficient correlation has been proposed with the change of fluid temperature considered by multiplying a temperature correction factor. It has been proven that the average relative prediction errors of heat transfer coefficient reduced from 19.08% to 4.98% for the wet Tank Wall of the Tank, from 8.93% to 4.27% for the dry Tank Wall, respectively, calculated by the modified correlation.

Suresh V Garimella - One of the best experts on this subject based on the ideXlab platform.

  • thermomechanical simulation of the solar one thermocline storage Tank
    2012
    Co-Authors: Scott M Flueckiger, Zhen Yang, Suresh V Garimella
    Abstract:

    The growing interest in large-scale solar power production has led to a renewed exploration of thermal storage technologies. In a thermocline storage system, heat transfer fluid (HTF) from the collection field is simultaneously stored at both excited and dead thermal states inside a single Tank by exploiting buoyancy forces. A granulated porous medium included in the Tank provides additional thermal mass for storage and reduces the volume of HTF required. While the thermocline Tank offers a low-cost storage option, thermal ratcheting of the Tank Wall (generated by reorientation of the granular material from continuous thermal cycling) poses a significant design concern. A comprehensive simulation of the 170 MWht thermocline Tank used in conjunction with the Solar One pilot plant is performed with a multidimensional two-temperature computational fluid dynamics model to investigate ratcheting potential. In operation from 1982 to 1986, this Tank was subject to extensive instrumentation, including multiple strain gages along the Tank Wall to monitor hoop stress. Temperature profiles along the Wall material are extracted from the simulation results to compute hoop stress via finite element models and compared with the original gage data. While the strain gages experienced large uncertainty, the maximum predicted hoop stress agrees to within 6.8% of the maximum stress recorded by the most reliable strain gages.

  • an integrated thermal and mechanical investigation of molten salt thermocline energy storage
    2011
    Co-Authors: Scott M Flueckiger, Zhen Yang, Suresh V Garimella
    Abstract:

    Thermal ratcheting is a critical phenomenon associated with the cyclic operation of dual-medium thermocline Tanks in solar energy applications. Although thermal ratcheting poses a serious impediment to thermocline operation, this failure mode in dual-medium thermocline Tanks is not yet well understood. To study the potential for the occurrence of ratcheting, a comprehensive model of a thermocline Tank that includes both the heterogeneous filler region as well as the composite Tank Wall is formulated. The filler region consists of a rock bed with interstitial molten salt, while the Tank Wall is composed of a steel shell with two layers of insulation (firebrick and ceramic). The model accounts separately for the rock and molten-salt regions in view of their different thermal properties. Various heat loss conditions are applied at the external Tank surface to evaluate the effect of energy losses to the surroundings. Hoop stresses, which are governed by the magnitude of temperature fluctuations, are determined through both a detailed finite-element analysis and simple strain relations. The two methods are found to yield almost identical results. Temperature fluctuations are damped by heat losses to the surroundings, leading to a reduction in hoop stresses with increased heat losses. Failure is prevented when the peak hoop stress is less than the material yield strength of the steel shell. To avoid ratcheting without incurring excessive energy loss, insulation between the steel shell and the filler region should be maximized.

Muhammad M Rahman - One of the best experts on this subject based on the ideXlab platform.

  • forced convective mixing in a zero boil off cryogenic storage Tank
    2012
    Co-Authors: Muhammad M Rahman
    Abstract:

    Abstract This paper presents the results of a study of fluid flow and heat transfer of liquid hydrogen in a cryogenic storage Tank with a heat pipe and an array of pump-nozzle units. A forced flow is directed onto the evaporator section of the heat pipe to prevent the liquid from boiling off when heat leaks through the Tank Wall insulation from the surroundings. An axisymmetric computational model was developed for the simulation of convective heat transfer in the system. Steady-state velocity and temperature fields were solved from this model by using the finite element method. Forty five configurations of geometry and velocity were considered. As the nozzle fluid speed increases, the values of the maximum, average, and spatial standard deviation of the temperature field decrease nonlinearly. Parametric analysis indicates that overall thermal performance of the system can be significantly improved by reducing the gap between the nozzle and the heat pipe, while maintaining the same fluid speed exiting the nozzle. It is also indicated that increased inlet tube length of the pump-nozzle unit results in slightly better thermal performance. Increased heat pipe length also improves thermal performance but only for low fluid speed.

  • three dimensional analysis for liquid hydrogen in a cryogenic storage Tank with heat pipe pump system
    2008
    Co-Authors: Son H Ho, Muhammad M Rahman
    Abstract:

    Abstract This paper presents a study on fluid flow and heat transfer of liquid hydrogen in a zero boil-off cryogenic storage Tank in a microgravity environment. The storage Tank is equipped with an active cooling system consisting of a heat pipe and a pump–nozzle unit. The pump collects cryogen at its inlet and discharges it through its nozzle onto the evaporator section of the heat pipe in order to prevent the cryogen from boiling off due to the heat leaking through the Tank Wall from the surroundings. A three-dimensional (3-D) finite element model is employed in a set of numerical simulations to solve for velocity and temperature fields of liquid hydrogen in steady state. Complex structures of 3-D velocity and temperature distributions determined from the model are presented. Simulations with an axisymmetric model were also performed for comparison. Parametric study results from both models predict that as the speed of the cryogenic fluid discharged from the nozzle increases, the mean or bulk cryogenic fluid speed increases linearly and the maximum temperature within the cryogenic fluid decreases.

I Gonzalez - One of the best experts on this subject based on the ideXlab platform.

  • thermo mechanical parametric analysis of packed bed thermocline energy storage Tanks
    2016
    Co-Authors: I Gonzalez, C D Perezsegarra, O Lehmkuhl, S Torras, A Oliva
    Abstract:

    A packed-bed thermocline Tank represents a proved cheaper thermal energy storage for concentrated solar power plants compared with the commonly-built two-Tank system. However, its implementation has been stopped mainly due to the vessel’s thermal ratcheting concern, which would compromise its structural integrity. In order to have a better understanding of the commercial viability of thermocline approach, regarding energetic effectiveness and structural reliability, a new numerical simulation platform has been developed. The model dynamically solves and couples all the significant components of the subsystem, being able to evaluate its thermal and mechanical response over plant normal operation. The filler material is considered as a cohesionless bulk solid with thermal expansion. For the stresses on the Tank Wall the general thermoelastic theory is used. First, the numerical model is validated with the Solar One thermocline case, and then a parametric analysis is carried out by settling this storage technology in two real plants with a temperature rise of 100°C and 275°C. The numerical results show a better storage performance together with the lowest temperature difference, but both options achieve suitable structural factors of safety with a proper design.