Experimental Study of the Characteristics of Heat Transfer in an HLMC Cross-Flow around Tubes

2015 ◽  
Vol 1 (4) ◽  
Author(s):  
Aleksei Chernysh ◽  
Mikhail Iarmonov ◽  
Kirill Makhov ◽  
Aleksandr Beznosov
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Liquid Metal ◽  
Experimental Studies ◽  
Cross Flow ◽  
Velocity Fields ◽  
Temperature Fields ◽  
Experimental Site ◽  
Lead Coolant ◽  
Velocity And Temperature Fields

The process of heat transfer in a heavy liquid-metal coolant (HLMC) cross-flow around heat-transfer tubes has not been thoroughly studied yet. Therefore, it is of great interest to carry out experimental studies for determining the heat-transfer characteristics in lead coolant cross-flow around tubes. It is also interesting to explore the velocity and temperature fields in an HLMC flow. To achieve this goal, experts of the R.E. Alekseev Nizhny Novgorod State Technical University performed work aimed at experimental determination of the temperature and velocity fields in high-temperature lead coolant cross-flows around a tube bundle. The experimental studies were carried out in a specially designed high-temperature liquid-metal facility. The experimental facility is a combination of two high-temperature liquid-metal setups, i.e., FT-2 with a lead coolant and FT-1 with a lead-bismuth coolant, combined by an experimental site. The experimental site is a model of the steam generator of the BREST reactor facility. The heat-transfer surface is an in-line tube bank of diameter 17 mm and wall thickness of 3.5 mm, which is made of 10H9NSMFB ferritic–martensitic steel. The temperature of the heat-transfer surface is measured with thermocouples of diameter 1 mm installed in the walls of heat-transfer tubes. The velocity and temperature fields in a high-temperature HLMC flow are measured with special sensors installed in the flow cross-section between rows of heat-transfer tubes. The characteristics of heat transfer and velocity fields in a lead coolant flow were studied in different directions of the coolant flow: the vertical (“top-down” and “bottom-up” (Beznosov et al., 2013, “Experimental Studies of Thermal Hydraulics of a HLMC Flow Around Heat transfer Surfaces,” Proceedings of the 21st International Conference on Nuclear Engineering, ICONE21, Paper No. ICONE21-15248)) and the horizontal directions. The studies were conducted under the following operating conditions: the temperature of lead was t=450–500°C, the thermodynamic activity of oxygen was a=10−5–100, and the lead flow through the experimental site was Q=3–6  m3/h, which corresponds to coolant velocities of V=0.4–0.8  m/s. Comprehensive experimental studies of the characteristics of heat transfer in a lead coolant cross-flow around tubes have been carried out for the first time, and the dependences Nu=f(Pe) for a controlled and regulated content of the thermodynamically active oxygen impurity and sediments of impurities have been obtained. The effect of the oxygen impurity content in the coolant and characteristics of protective oxide coatings on the temperature and velocity fields in a lead coolant flow have been revealed. This is because the presence of oxygen in the coolant and oxide coatings on the surface, which restricts the liquid-metal flow, leads to a change in the characteristics of the wall-adjacent region. The obtained experimental data on the distribution of the velocity and temperature fields in an HLMC flow permit studying the heat-transfer processes, and on this basis, create program codes for engineering calculations of HLMC flows around heat-transfer surfaces.

Experimental Study of the Characteristics of Heat Transfer and HLMC Cross-Flow Around Tubes

2014 ◽  
Author(s):  
Aleksei Chernysh ◽  
Mikhail Iarmonov ◽  
Kirill Makhov ◽  
A. V. Beznosov
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Liquid Metal ◽  
Experimental Studies ◽  
Cross Flow ◽  
Velocity Fields ◽  
Temperature Fields ◽  
Experimental Site ◽  
Lead Coolant ◽  
Velocity And Temperature Fields

The process of heat transfer in a heavy liquid-metal coolant (HLMC) cross-flow around heat-transfer tubes is not yet thoroughly studied. Therefore, it is of great interest to carry out experimental studies for determining the heat transfer characteristics in a lead coolant cross-flow around tubes. It is also interesting to explore the velocity and temperature fields in a HLMC flow. To achieve this goal, experts of the R.E. Alekseev Nizhny Novgorod State Technical University performed the work aimed at the experimental determination of the temperature and velocity fields in high-temperature lead coolant cross-flows around a tube bundle. The experimental studies were carried out in a specially designed high-temperature liquid-metal facility. The experimental facility is a combination of two high-temperature liquid-metal setups, i.e., FT-2 with a lead coolant and FT-1 with a lead-bismuth coolant, united by an experimental site. The experimental site is a model of the steam generator of the BREST reactor facility. The heat-transfer surface is an in-line tube bank of a diameter of 17×3.5 mm, which is made of 10H9NSMFB ferritic-martensitic steel. The temperature of the heat-transfer surface is measured with thermocouples of a diameter of 1 mm being installed in the walls of heat-transfer tubes. The velocity and temperature fields in a high-temperature HLMC flow are measured with special sensors installed in the flow cross section between the rows of heat-transfer tubes. The characteristics of heat transfer and velocity fields in a lead coolant flow were studied in different directions of the coolant flow: the vertical (“top-down” and “bottom-up” [1]) and the horizontal ones. The studies were conducted under the following operating conditions: the temperature of lead was t=450–500°C, the thermodynamic activity of oxygen was a=10−5−100, and the lead flow through the experimental site was Q = 3–6 m3/h, which corresponds to coolant velocities of V = 0.4–0.8 m/s. Comprehensive experimental studies of the characteristics of heat transfer in a lead coolant cross-flow around tubes have been carried out for the first time and the dependences NU = f(Pe) for a controlled and regulated content of the thermodynamically active oxygen impurity and sediments of impurities have been obtained. The effect of the oxygen impurity content in the coolant and characteristics of protective oxide coatings on the temperature and velocity fields in a lead coolant flow is revealed. This is because the presence of oxygen in the coolant and oxide coatings on the surface, which restrict the liquid-metal flow, leads to a change in the characteristics of the wall-adjacent region. The obtained experimental data on the distribution of the velocity and temperature fields in a HLMC flow permit studying the heat-transfer processes and, on this basis, creating program codes for engineering calculations of HLMC flows around heat-transfer surfaces.

Experimental Studies of Thermal Hydraulics of a HLMC Flow Around Heat Exchange Surfaces

2013 ◽  
Author(s):  
Mikhail Iarmonov ◽  
Olga Novozhilova ◽  
Pavel Bokov ◽  
A. V. Beznosov
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchange ◽  
Experimental Studies ◽  
Velocity Fields ◽  
Operating Conditions ◽  
Coolant Flow ◽  
Oxygen Impurity ◽  
Lead Coolant ◽  
Temperature And Velocity Fields

Temperature and velocity fields in high-temperature lead coolant flows in a circular clearance for controlled oxygen impurity content in a flow were experimentally studied at the Nizhny Novgorod State Technical University by R.E. Alekseev (NNSTU). Temperature and velocity fields were simultaneously studied in “cold” and “hot” parts of the circuit in the following operating conditions: the lead temperature is t = 400–550 °C, the thermodynamic activity of oxygen is a = 10−5–100; the Peclet number is Pe = 500–7000, the coolant flow velocity is w = 0.1–1.5 m/s, and the average heat flux is q = 50–160 kW/m2. It has been found that the oxygen impurity content and characteristics of protective oxide coatings affect temperature and velocity fields in round and circular channels. This is due to the fact that oxygen in a coolant and oxide coatings on the surfaces limiting a liquid metal flow influence characteristics of the wall boundary region. The heat transfer process that occurs when HLMC transversely flows around heat exchange pipes is investigated now at the NNSTU. The experimental facility is a combination of two high-temperature liquid-metal stands, i.e., FT-2 with the lead coolant and FT-1 with the lead-bismuth coolant combined with an experimental section. The temperature of a heat-exchange surface is measured by thermocouples of diameter 1 mm mounted in walls of heat-exchange pipes. Velocity and temperature fields in a high-temperature HLMC flow are measured by special sensors placed in the flow cross section between rows of heat-exchange pipes. Heat transfer characteristics and temperature and velocity fields in a high-temperature lead coolant flow are studied in the following operating conditions: the lead temperature is t = 450–500 °C, the thermodynamic activity of oxygen is a = 10−5–100, and the coolant flow rate through the experimental setup is Q = 3–6 m3/h, which corresponds to coolant flow velocities of V = 0.4–0.8 m/s. Integrated experimental studies of characteristics of the heat transfer that occurs when the lead coolant transversely or obliquely flows around pipes have been carried out for the first time and the dependences Nu = f(Pe) for controlled content of thermodynamically active oxygen impurity and sediments of impurities have been obtained. It is assumed that the obtained experimental data on distribution of velocity and temperature fields in a HLMC flow will permit to study heat transfer processes and to use them for developing program codes for engineering calculations of heat exchange surfaces (steam generators) with a HLMC flow around them.

On Low-Dimensional Galerkin Modeling of Confined Twin-Jet Flow and Heat Transfer

2001 ◽  
Author(s):  
H. Gunes ◽  
K. Gocmen ◽  
L. Kavurmacioglu
Keyword(s):  
Heat Transfer ◽  
Jet Flow ◽  
Basis Functions ◽  
Galerkin Projection ◽  
Temperature Fields ◽  
Transitional Flow ◽  
Flow And Heat Transfer ◽  
Galerkin Models ◽  
Velocity And Temperature Fields ◽  
Low Dimensional

Abstract The two-dimensional incompressible non-isothermal confined twin-jet flow has been numerically studied in the transitional flow regime by a finite volume technique. Results have been obtained for the velocity and temperature distributions close to the onset of temporal oscillations. Next, the proper orthogonal decomposition (POD) is applied to the instantaneous flow and temperature data to obtain POD-based basis functions for both velocity and temperature fields. These basis functions are capable to identify the coherent structures in the velocity and temperature fields. The low-dimensional Galerkin models of the full Navier-Stokes and energy equations are constructed by the Galerkin projection onto basis functions. Since the low-dimensional Galerkin models are much easier to analyze than the full governing equations, basic insights into important mechanisms of dynamically complex flow and heat transfer (e.g. flow instabilities) can be easily studied by these models. The numerical implications, the validity of the models and their performance characteristics are discussed.

scholarly journals Temperature fields and heat transfer in free-packed pin bundles cooled by heavy liquid-metal

2015 ◽  
Vol 2015 (4) ◽  
pp. 90-100 ◽  
Author(s):  
Albert Vladimirovich Zhukov ◽  
Juliya Al’bertovna Kuzina ◽  
Aleksandr Pavlovich Sorokin ◽  
Vitalij Vladimirovich Privezentsev
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Temperature Fields ◽  
Heavy Liquid

Design of High Temperature and High Pressure Petroleum Bullets Performance Test Device

2012 ◽  
Vol 580 ◽  
pp. 346-349
Author(s):  
Xiao Qing Li ◽  
Ren Qiang Liu ◽  
Da Zhong Hua ◽  
Xiao Yan Liu
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
High Temperature ◽  
Performance Test ◽  
Convection Heat Transfer ◽  
Local Area ◽  
Temperature Fields ◽  
Test Time ◽  
Test Device ◽  
High Pressure Reaction

A high temperature and high pressure reaction autoclave for petroleum bullets performance test is designed in this paper. Heat transfer in both vertical and horizontal reaction autoclave structure is analyzed and calculated. Considering system heat loss, heating power of these two kinds of devices is calculated in different test time. Meanwhile, temperature fields in these two kinds of autoclave are simulated. According to the comparison result, the authors come to the conclusion that temperature field in vertical reaction autoclave is uniform and can meet design demand with a temperature difference less than ±5°C. Horizontal reaction autoclave in which there are small eddies in air interlayer cannot meet demand because eddies enhance the convection heat transfer in local area. Based on this conclusion, a reasonable reaction autoclave structure can be designed.

Development of High Temperature Liquid Metal Heat Transfer Fluids for CSP Applications

2014 ◽  
Author(s):  
Gopinath R. Warrier ◽  
Y. Sungtaek Ju ◽  
Jan Schroers ◽  
Mark Asta ◽  
Peter Hosemann
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Liquid Metal ◽  
Liquid Metals ◽  
Research Effort ◽  
Structural Materials ◽  
Forced Flow ◽  
Oxygen Control ◽  
Ongoing Research ◽  
Heat Transfer Fluids

In response to the DOE Sunshot Initiative to develop low-cost, high efficiency CSP systems, UCLA is leading a multi-university research effort to develop new high temperature heat transfer fluids capable of stable operation at 800°C and above. Due to their operating temperature range, desirable heat transfer properties and very low vapor pressure, liquid metals were chosen as the heat transfer fluid. An overview of the ongoing research effort is presented. Development of new liquid metal coolants begins with identification of suitable candidate metals and their alloys. Initial selection of candidate metals was based on such parameters as melting temperature, cost, toxicity, stability/reactivity Combinatorial sputtering of the down selected candidate metals is used to fabricate large compositional spaces (∼ 800), which are then characterized using high-throughput techniques (e.g., X-ray diffraction). Massively parallel optical methods are used to determine melting temperatures. Thermochemical modeling is also performed concurrently to compliment the experimental efforts and identify candidate multicomponent alloy systems that best match the targeted properties. The modeling effort makes use of available thermodynamic databases, the computational thermodynamic CALPHAD framework and molecular-dynamics simulations of molten alloys. Refinement of available thermodynamics models are performed by comparison with available experimental data. Characterizing corrosion in structural materials such as steels, when using liquid metals, and strategies to mitigate them are an integral part of this study. The corrosion mitigation strategy we have adopted is based on the formation of stable oxide layers on the structural metal surface which prevents further corrosion. As such oxygen control is crucial in such liquid metal systems. Liquid metal enhanced creep and embrittlement in commonly used structural materials are also being investigated. Experiments with oxygen control are ongoing to evaluate what structural materials can be used with liquid metals. Characterization of the heat transfer during forced flow is another key component of the study. Both experiments and modeling efforts have been initiated. Key results from experiments and modeling performed over the last year are highlighted and discussed.

Flow Dynamics Over Two Cylinders in Tandem Subjected to Different Heating Cases

2021 ◽  
Author(s):  
Rami Homsi ◽  
MD Islam ◽  
Yap Yit Fatt ◽  
Isam Janajreh
Keyword(s):  
Heat Transfer ◽  
Cross Flow ◽  
Temperature Fields ◽  
Circular Cylinders ◽  
Transfer Coefficients ◽  
Extended Body ◽  
Heat Transfer Coefficients ◽  
Velocity Magnitude ◽  
Fluid Properties ◽  
Limiting Case

Abstract Heated and unheated flows with forced convection over two fixed circular cylinders in tandem are studied numerically for 80 ≤ Re ≤ 250 and 1 ≤ T* ≤ 2.3. Three different spacing ratios (L/D) = [2, 4, 8] are considered under three heating conditions. The scenarios considered are (1) heated upstream and unheated downstream cylinders, (2) unheated upstream and heated downstream cylinders and (3) heated upstream and downstream cylinders. These scenarios represent the limiting case for a cross-flow heat exchanger, where the downstream tubes are at increasingly lower or higher temperature for cooling or heating, respectively. The global aerodynamic forces on the cylinder as vortices shed was investigated. The flow is visualized by plotting the streamlines, temperature fields, and velocity magnitude contours for the different spacing ratios and compared to the flow regimes in literature namely, Extended-body, Reattachment, and Co-shedding regimes. The drag and surface heat transfer coefficients are analyzed for different scenarios. The effect of heating on the fluid properties and the resulted wakes in the flow are found to be strongly influenced by Re and L/D. The scenario of heated upstream and unheated downstream cylinders was found to increase the mean drag coefficient Cd on the upstream cylinder for L/D = 2 & 4 but is not as evident for the downstream cylinder. The heat transfer coefficient h on the upstream cylinder remained approximately the same regardless of a heated or unheated downstream cylinder. In contrast, h of the downstream cylinder decreases for the scenario of heated upstream and downstream cylinder.

Flow and Heat Transfer of Confined Impingement Jets Cooling

2000 ◽  
Author(s):  
Ting Wang ◽  
Mingjie Lin ◽  
Ronald S. Bunker
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Flow Structure ◽  
Experimental Studies ◽  
Cross Flow ◽  
Jet Impingement ◽  
Target Surface ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Transfer Behavior

Experimental studies on heat transfer and flow structure in confined impingement jets were performed. The objective of this study was to investigate the detailed heat transfer coefficient distribution on the jet impingement target surface and flow structure in the confined cavity. The distribution of heat transfer coefficients on the target surface was obtained by employing the transient liquid crystal method coupled with a 3-D inverse transient conduction scheme under Reynolds number ranging from 1039 to 5175. The results show that the average heat transfer coefficients increased linearly with the Reynolds number as Nu = 0.00304 Pr0.42Re. The effects of cross flow on heat transfer were investigated. The flow structure were analyzed to gain insight into convective heat transfer behavior.

Heat Transfer Enhancement in Corrugated Pipes

2010 ◽  
Author(s):  
Dennis A. Siginer ◽  
F. Talay Akyildiz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Heat Transfer Enhancement ◽  
Temperature Fields ◽  
Governing Equations ◽  
Transfer Enhancement ◽  
Exact Analytical Solutions ◽  
Velocity And Temperature Fields ◽  
Steady Laminar

The temperature distribution and heat transfer coefficient are investigated in forced convection with Newtonian fluids in pressure gradient driven hydrodynamically and thermally fully developed steady laminar flow in transversally corrugated pipes. The governing equations are solved by means of the epitrochoid conformal mapping and exact analytical solutions are derived for the velocity and temperature fields without viscous dissipation. The effect of the corrugations and the number of waves on the friction factor, the temperature distribution and the heat transfer enhancement is discussed.

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