scholarly journals Cooling Caramel in Ethyl Alcohol: Constructing a Mathematical Model

2020 ◽  
Vol 50 (3) ◽  
pp. 425-438
Author(s):  
Anatoly Khvostov ◽  
Gazibeg Magomedov ◽  
Viktor Ryazhskikh ◽  
Inessa Plotnikova ◽  
Aleksey Zhuravlev ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
High Performance ◽  
Experimental Studies ◽  
Transient Heat Conduction ◽  
Flow Speed ◽  
Model Parameters ◽  
Air Cooling ◽  
Radial Temperature ◽  
Cooling Period

Introduction. The process of air-cooling caramel remains one of the most complicated issues of contemporary food industry, since it is time-consuming and requires multi-level cooling units. Therefore, the development of an innovative method of cooling caramel in “cold” potable ethanol is an urgent task the modern food science has to solve. The method op-timizes and intensifies the technological process, as it reduces production areas by eliminating some technological stages and complex units of metal-intensive and energyintensive equipment. It gives caramel antiseptic properties and a perfectly smooth, shiny, and dry surface. Study objects and methods. The research objective was to develop a fundamentally new and promising caramel technology. The experimental studies on the production and cooling were performed in a mixing and forming multi-unit with a high-performance cooling chamber. The chamber had functions of automatic measurements and control of the main parameters of the cooling process. The research used “cold” potable ethanol. Results and discussion. The paper introduces a mathematical model of the process of cooling caramel in ethanol. It includes heat transfer processes in alcohol, in the caramel mass, and on their border. The model was based on equations of transient heat conduction in a sphere. The process of heat exchange with the environment, i.e. alcohol, was characterized by the coefficient of heat transfer from the sphere. The model parameters included dynamic viscosity, density, thermal conductivity coefficient, and specific heat capacity. Based on the experimental data, the parameters were ap-proximated as a function of temperature by a cubic polynomial. Conclusion. The developed mathematical model made it possible to estimate the radial temperature distribution of caramel in the form of a sphere during its convective cooling in ethanol. The model also predicted the change in the average volume temperature of the caramel and energy costs depending on the cooling period, the flow speed of the ethanol, the thermophysical properties of the caramel and the cooling agent. The proposed mathematical model can be used to calculate the required consumption of ethanol for cooling and backwater of the caramel production line.

Effect of Film-Cooling Hole Location on Turbulator Heat Transfer Enhancement in Turbine Blade Internal Air-Cooling Circuits

1999 ◽  
Author(s):  
J. M. McDonough ◽  
V. E. Garzón ◽  
D. E. Schulte
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
High Performance ◽  
Turbulence Modeling ◽  
Pressure Coefficient ◽  
Turbine Blades ◽  
Air Cooling ◽  
Eddy Simulation ◽  
Cooling Hole ◽  
Cooling Air

Numerical results demonstrating the effect of film-cooling hole placement on turbulator heat transfer effectiveness in internal convective cooling air circuits of turbine blades in high-performance gas turbine engines is presented for a two-dimensional model problem. Of particular interest will be the performance of a new turbulence modeling formalism similar to large-eddy simulation (LES) but employing subgrid-scale models constructed from nonlinear discrete dynamical systems, and not requiring filtering of the resolved-scale governing equations. Computed results for temperature distribution, flow streamlines, pressure coefficient and heat transfer Stanton number are compared for three different cooling hole/turbulator configurations, and turbulence kinetic energy is compared with results from a standard k-ε model.

Study on a New Mathematical Model for Aggregate Air Cooling or Heating

2011 ◽  
Vol 374-377 ◽  
pp. 1882-1886
Author(s):  
Li Juan Wang ◽  
Yan Feng Liu ◽  
Jia Ping Liu ◽  
Fei Lu
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Hydraulic Structure ◽  
Surface Heat ◽  
Air Cooling ◽  
Foundation Engineering ◽  
Heating Capacity ◽  
Surface Heat Transfer Coefficient

Before the construction of hydraulic structure, aggregate must be cooled or heated by air (we call it aggregate air cooling or heating in this paper) or other technologies to the required temperature. Previous model of aggregate air cooling or heating cannot provide the center temperature of each aggregate. So a more accurate mathematical model is developed to determine the thermal performance of aggregate, and the surface heat transfer coefficient of wet aggregate is revised. This model can predict the center temperature of an aggregate and can accurately calculate the cold down time or temperature distribution of aggregate, so that the refrigeration or heating capacity can be reasonably supplied. It’s significant for foundation engineering of hydraulic structure.

scholarly journals Experimental studies of iron transformations kinetics and autocatalysis during its physicochemical removal from underground water

2021 ◽  
Author(s):  
S. Yu Martynov ◽  
V. L. Poliakov
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Experimental Studies ◽  
Underground Water ◽  
Model Parameters ◽  
Kinetic Coefficients ◽  
Transfer Equations ◽  
The Mathematical Model ◽  
Autocatalytic Effect ◽  
Forms Of Iron

Abstract The mathematical model of physicochemical iron removal from groundwater was developed. It consists of three interrelated compartments. The results of the experimental research provide information in support of the first two compartments of the mathematical model. The dependencies for the concentrations of the adsorbed ferrous iron and deposited hydroxide concentrations are obtained as a result of the exact solution of the system of the mass transfer equations for two forms of iron in relation to the inlet surface of the bed. An analysis of the experimental data of the dynamics of the deposit accumulation in a small bed sample was made, using a special application that allowed to select the values of the kinetic coefficients and other model parameters based on these dependencies. We evaluated the autocatalytic effect on the dynamics of iron ferrous and ferric forms. The verification of the mathematical model was carried out involving the experimental data obtained under laboratory and industrial conditions.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2019 ◽  
Author(s):  
Ganesh Guggilla ◽  
Arvind Pattamatta ◽  
Ramesh Narayanaswamy
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Heated Surface ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

Sensitivity Analysis of One-Dimensional Heat Transfer in Tissue With Temperature-Dependent Perfusion

1997 ◽  
Vol 119 (1) ◽  
pp. 77-80 ◽  
Author(s):  
C. R. Davies ◽  
G. M. Saidel ◽  
H. Harasaki
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Heated Surface ◽  
Experimental Studies ◽  
Total Artificial Heart ◽  
Tissue Temperature ◽  
Model Parameters ◽  
Temperature Dependent ◽  
One Dimensional

Design criteria for implantable, heat-generating devices such as the total artificial heart require the determination of safe thresholds for chronic heating. This involves in-vivo experiments in which tissue temperature distributions are obtained in response to known heat sources. Prior to experimental studies, simulation using a mathematical model can help optimize the design of experiments. In this paper, a theoretical analysis of heat transfer is presented that describes the dynamic, one-dimensional distribution of temperature from a heated surface. Loss of heat by perfusion is represented by temperature-independent and temperature-dependent terms that can reflect changes in local control of blood flow. Model simulations using physiologically appropriate parameter values indicate that the temperature elevation profile caused by a heated surface adjacent to tissue may extend several centimeters into the tissue. Furthermore, sensitivity analysis indicates the conditions under which temperature profiles are sensitive to changes in thermal diffusivity and perfusion parameters. This information provides the basis for estimation of model parameters in different tissues and for prediction of the thermal responses of these tissues.

Tungsten Powder Sintering

2016 ◽  
Vol 712 ◽  
pp. 237-240 ◽  
Author(s):  
E.S. Dvilis ◽  
Anna G. Knyazeva ◽  
Svetlana N. Sorokova ◽  
Oleg L. Khasanov
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Matrix Composite ◽  
Conjugate Heat Transfer ◽  
Tungsten Powder ◽  
Experimental Studies ◽  
Synthesis Process ◽  
Porosity Evolution ◽  
Powder Sintering ◽  
The Mathematical Model

The results of theoretical and experimental studies of the synthesis process by the electric sintering of aluminum is a matrix composite. The mathematical model takes into account the conjugate heat transfer and porosity evolution.

scholarly journals Using Bifurcation Theory for Exploring Pain

2019 ◽  
Author(s):  
Parul Verma ◽  
Achim Kienle ◽  
Dietrich Flockerzi ◽  
Doraiswami Ramkrishna
Keyword(s):  
Mathematical Model ◽  
Electrical Activity ◽  
Bifurcation Theory ◽  
Experimental Studies ◽  
Specific Model ◽  
Computational Approach ◽  
Model Parameters ◽  
Pain Response ◽  
Response Mechanism ◽  
Pain Sensation

AbstractPain is a common sensation which inescapably arises due to injuries, as well as, various diseases and disorders. However, for the same intensity of disturbance arising due to the forgoing causes, the threshold for pain sensation and perception varies among individuals. Here, we present a computational approach using bifurcation theory to understand how the pain sensation threshold varies and how it can be controlled, the threshold being quantified by the electrical activity of a pain-sensing neuron. To this end, we explored the bifurcations arising from a mathematical model representing the dynamics of this neuron. Our findings indicate that the bifurcation points are sensitive to specific model parameters. This demonstrates that the pain sensation threshold can change as shown in experimental studies found in literature. Further investigation using our bifurcation approach coupled with experimental studies can facilitate rigorous understanding of pain response mechanism and provide strategies to control the pain sensation threshold.

scholarly journals MATHEMATICAL MODEL OF HEAT TRANSFER IN A MICROCHANNEL HEAT PIPE WITH CIRCULATING TWO-PHASE FLOW

2020 ◽  
Vol 55 ◽  
pp. 62-67
Author(s):  
Rufat Sh. Abiev ◽  
◽  
Ritunesh Kumar ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Pipe ◽  
Two Phase Flow ◽  
Experimental Studies ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Proof ◽  
Oscillating Heat Pipe ◽  
Taylor Flow

In addition to the previously created hydrodynamics model, a mathematical model describing the heat transfer parameters of two-phase flow is constructed. Particular role of longitudinal convection in the heat transport is shown. The experimental studies confirmed a microchannel heat pipe operability with a two-phase flow in a circulating mode. A circulating two-phase Taylor flow in microchannel was considered to be more efficient for overall heat transfer in a heat pipe compared to the pulsating (oscillating) heat pipe. The advantages of circulating two-phase Taylor flow related to the pulsating heat pipes are discussed on the proposed mathematical model basis. The conditions of experimental proof of the proposed mathematical model were elaborated.

scholarly journals Determination of temperature distribution on windings of oil transformer based on the laws of heat transfer

ScienceRise ◽  
2021 ◽  
pp. 3-13
Author(s):  
Volodymyr Grabko ◽  
Stanislav Tkachenko ◽  
Oleksandr Palaniuk
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Distribution ◽  
Simulation Model ◽  
Power Transformer ◽  
Experimental Studies ◽  
Short Term ◽  
Transformer Winding ◽  
Transformer Equipment ◽  
Technological Product

Object of research: development of a technology for determining the temperature of the winding of a power oil transformer, in particular, the analysis of thermal processes in the winding of a power transformer during short-term overloads, taking into account the influence of the environment. Investigated problem: temperature distribution in the winding of a power oil transformer taking into account short-term load surges in the problem of assessing the residual life of the insulation of the transformer winding by temperature aging. The calculation of the temperature distribution in the winding was carried out using the passport data and characteristics of the power oil transformer, including the winding, transformer oil, load currents. Main scientific results: a mathematical model was calculated, with the help of which the results of temperature distribution in the transformer winding were obtained during short-term load surges or constant work with an increased load. According to the presented model, the analysis of the cooling time of the transformer winding after short-term overloads is carried out. Comparing the results obtained on the simulation model with the known results of experimental studies of the temperature distribution in the winding of a power transformer, the adequacy of the mathematical model is proved. It is shown that the use of the laws of heat transfer in a homogeneous plate to analyze the temperature distribution in the transformer winding is not wrong, but requires clarifications and simplifications. The area of practical use of the research results: enterprises of the machine-building industry and energy companies specializing in the production and operation of transformer equipment. Innovative technological product: simulation model of heat distribution in a transformer winding, which can take into account the load of the transformer, the effect of the environment on the insulation of the transformer windings. An innovative technological product: a method for diagnosing the duration of the non-failure operation of a transformer, which makes it possible to ensure trouble-free operation and save money for the repair of transformer equipment. Scope of application of the innovative technological product: design and development of diagnostic systems for windings of power oil transformers

scholarly journals Experimental Investigation of Thermal and Hydraulic Characteristics of Finned Flat Tubes of the Oil Air Cooling Device

2020 ◽  
Vol 63 (2) ◽  
pp. 138-150 ◽  
Author(s):  
S. V. Tiunov ◽  
A. N. Skrypnik ◽  
G. S. Marshalova ◽  
V. M. Gureev ◽  
I. A. Popov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Thermal Power ◽  
Experimental Studies ◽  
Performance Criteria ◽  
Maximum Height ◽  
Air Cooling ◽  
Cooling Device ◽  
Transfer Resistance ◽  
Cooling Devices

Air cooling devices are heat exchange units that are widely used in practice. However, they have a number of disadvantages due to the low value of the heat transfer coefficient from the air and the high resistance of finned tube bundles, which leads to large dimensions and the metal content of the device itself, to the need to develop a high power ventilator drive, but also to the need to demonstrate reduced energy efficiency. The objective of the present work is to determine optimal geometric sizes of finned flat heat exchange tubes manufactured by the techniques of extrusion and deforming cutting that reduce the weight and size characteristics of the heat exchange section of air cooling devices. The experimental studies of seven various samples of heat exchange sections, being different in fin pitch and height, tube section width, flat tube height and a number of inner channels, have determined the performance of each section with the use of the following criteria: thermal power, thermal efficiency, specific thermal heat transfer resistance, M. V. Kirpichev and V. M. Antuf’ev’s criteria. The obtained experimental data and the analysis of the passive method of enhancement in the near-wall area of the heat transfer surface finned by deforming cutting has shown that sample No 5 has maximum value of the performance criteria when the maximum height of a fin is 0.008 m and the minimum pitch of a fin is 0.0025 m over the investigated sample range. Thus, when the sizes of an oil air cooling device are maintained by using the amended heat transfer section of sample No 5, the amount of removed heat can be increased or the mass and dimensions of the device can be decreased while maintaining thermal power and, as a result, the power consumption for pumping can be decreased and the thermal-hydraulic performance of the device as a whole can be increased.

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