A Helium II Heat Transfer Level Meter

2000 ◽  
Author(s):  
T. Zhang ◽  
M. R. Smith ◽  
S. W. Van Sciver
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Measurement Techniques ◽  
Liquid Level ◽  
Heat Transfer Analysis ◽  
New Type ◽  
Measurement Principle ◽  
Level Meter ◽  
Helium Level ◽  
The Relationship

Abstract This paper presents the design and measurement techniques for a new type of liquid helium level meter. The measurement principle is given by the change of heat transfer rate with the liquid level. Detailed heat transfer analysis has been done to show the anticipated behavior and accuracy of the meter. To verify our design, a prototype level meter was fabricated and tested in saturated He II bath with temperature from 1.7 K to 2.0 K. With the experiment, we obtained the relationship between overall heater power and liquid level. The data indicate that the device can measure liquid level with the uncertainty of ±1 mm in a practical system.

Design of a Plane-Type Bidirectional Thermal Diode

1988 ◽  
Vol 110 (4) ◽  
pp. 299-305 ◽  
Author(s):  
K. Chen
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Transfer Rate ◽  
Reverse Bias ◽  
Energy Utilization ◽  
Heat Transfer Analysis ◽  
Transfer Rates ◽  
One Dimensional ◽  
Plane Type ◽  
Solar Energy Utilization

The design of a plane-type, bidirectional thermal diode is presented. This diode is composed of two vertical plates and several fluid-filled loops with their horizontal segments soldered to the vertical plates. This invention is simple in construction and low in cost. The direction of heat transfer in the invented thermal diode can be easily reversed. These features of the present invention make it very attractive to solar energy utilization. Natural convection analysis for thermosyphon operations was adopted for heat transfer calculations of the fluid-filled loops. A one-dimensional heat transfer analysis was employed to estimate the heat transfer rate and ratio of heat transfer rates of the diode under forward and reverse bias.

scholarly journals Improvement on the Calculation of Heat Transfer Rate for a New Type of Geothermal Energy Pile

IFCEE 2021 ◽  
2021 ◽  
Author(s):  
Yong Zou ◽  
Jie Huang ◽  
Fei Wang ◽  
John S. McCartney ◽  
Elahe Jafari
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Geothermal Energy ◽  
Transfer Rate ◽  
Energy Pile ◽  
New Type

Transient Heat Analysis in a Two-Step Radiative Combustible Slab

2021 ◽  
Vol 872 ◽  
pp. 15-19
Author(s):  
Ramoshweu Solomon Lebelo ◽  
Kholeka Constance Moloi
Keyword(s):  
Heat Transfer ◽  
Kinetic Parameters ◽  
Chemical Reaction ◽  
Transfer Rate ◽  
Heat Transfer Analysis ◽  
Shooting Technique ◽  
Surrounding Environment ◽  
Article Analysis ◽  
Exothermic Chemical Reaction ◽  
Rectangular Slab

In this article, analysis of heat transfer in a stockpile of reactive materials modelled in a rectangular slab is carried out. A two-step exothermic chemical reaction is assumed and the heat loss to the surrounding environment is by radiation. The ordinary differential equation (ODE) governing the problem is tackled numerically by Runge-Kutta Fehlberg (RKF45) method coupled with Shooting technique. The heat transfer analysis is simplified by investigation some kinetic parameters’ effects on the temperature of the combusting system. It was found out that some kinetic parameters raise the levels of the temperature by encouraging the exothermic chemical reaction, whereas some, reduce the levels of the temperature to slow down the heat transfer rate. The results are depicted graphically and discussed accordingly.

Heat Transfer Analysis of Shell-and-Helical-Coil Heat Exchangers

2016 ◽  
Author(s):  
Anthony Edward Morris ◽  
C. S. Wei ◽  
Runar Unnthorsson ◽  
Robert Dell
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Heat Exchangers ◽  
Transfer Rate ◽  
Green Roofs ◽  
Heat Transfer Analysis ◽  
Helical Coil ◽  
Straight Tube ◽  
Science And Art ◽  
Coil Heat

Since 2006, The Center for Innovation and Applied Technology (CIAT) at Cooper Union for the Advancement of Science and Art has been developing a system to use thermal pollution to heat the growth medium of green roofs. CIAT is researching various apparatus and techniques, including shell-and-tube and shell-and-coil heat exchangers, to improve its heated ground agricultural projects. There are limited recorded observations on shell-and-coil heat exchangers; therefore a laboratory work station was created of interchangeable components to test the efficiency of a variety of coil designs. This paper discusses the data collected on temperature, pressure, and flow rates for a straight tube and two different helical coils. The analysis of this data indicates the superiority of a helical coil design when compared to a straight tube design with respect to both rating and heat transfer rate. The same data analysis has lead to preliminary observations on how the contour properties of a helical coil influence the heat transfer rate through a coil. The authors intend to further this helical coil research to develop a useful mathematical model for determining efficient designs for shell-and-coil heat exchangers.

Hot Water Immersion To Eliminate Escherichia coli O157:H7 on the Surface of Whole Apples: Thermal Effects and Efficacy

2001 ◽  
Vol 64 (4) ◽  
pp. 451-455 ◽  
Author(s):  
G. J. FLEISCHMAN ◽  
C. BATOR ◽  
R. MERKER ◽  
S. E. KELLER
Keyword(s):  
Heat Transfer ◽  
Escherichia Coli ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Water Immersion ◽  
Hot Water ◽  
Heat Transfer Analysis ◽  
Escherichia Coli O157 ◽  
Transfer Coefficients ◽  
Hot Water Immersion

The effect of hot water immersion on both the reduction of Escherichia coli O157:H7 on the apple surface and internal temperatures of the apple was assessed in this study. Microbial reductions were measured experimentally, whereas internal temperatures were calculated through a mathematical analysis of experimental heat transfer data obtained from the apples. A method was developed to provide a purely surface-based inoculation of E. coli O157:H7. Rinsing produced no reduction, and treatments at 80 and 95°C produced reductions of more than 5 logs in 15 s or less. The heat transfer analysis based on experimental data was used to calculate surface heat transfer coefficients and predict temperatures throughout the apple. The analysis indicated a low heat transfer rate. Although it reduces thermal degradation, a low heat transfer rate precludes thermal-based reduction of any internalized microorganisms.

scholarly journals Numerical treatment of radiative Nickel–Zinc ferrite-Ethylene glycol nanofluid flow past a curved surface with thermal stratification and slip conditions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Muhammad Ramzan ◽  
Nosheen Gul ◽  
Jae Dong Chung ◽  
Seifedine Kadry ◽  
Yu-Ming Chu
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Heat Transfer Rate ◽  
Heat Generation ◽  
Transfer Rate ◽  
Thermal Stratification ◽  
Zinc Ferrite ◽  
Curved Surface ◽  
Heat Transfer Analysis ◽  
Nickel Zinc

Abstract The inadequate cooling capacity of the customary fluids forced the scientists to look for some alternatives that could fulfill the industry requirements. The inception of nanofluids has revolutionized the modern industry-oriented finished products. Nanofluids are the amalgamation of metallic nanoparticles and the usual fluids that possess a high heat transfer rate. Thus, meeting the cooling requirements of the engineering and industrial processes. Having such amazing traits of nanofluids in mind our aim here is to discuss the flow of nanofluid comprising Nickel–Zinc Ferrite and Ethylene glycol over a curved surface with heat transfer analysis. The heat equation contains nonlinear thermal radiation and heat generation/absorption effects. The envisioned mathematical model is supported by the slip and the thermal stratification boundary conditions. Apposite transformations are betrothed to obtain the system of ordinary differential equations from the governing system in curvilinear coordinates. A numerical solution is found by applying MATLAB build-in function bvp4c. The authentication of the proposed model is substantiated by comparing the results with published articles in limiting case. An excellent concurrence is seen in this case. The impacts of numerous physical parameters on Skin friction and Nusselt number and, on velocity and temperature are shown graphically. It is observed that heat generation/absorption has a significant impact on the heat transfer rate. It is also comprehended that velocity and temperature distributions have varied behaviors near and far away from the curve when the curvature is enhanced.

Thin-Film Heat-Flux Microsensor for Heat-Transfer Measurement in Micro-Heat Exchangers/Microreactors

2012 ◽  
Author(s):  
Houssein Ammar ◽  
David Hamadi ◽  
Bertrand Garnier ◽  
Ahmed Ould El Moctar ◽  
Hassan Peerhossaini ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Heat Exchangers ◽  
Measurement Techniques ◽  
Heat Transfer Analysis ◽  
Heat Flux Sensor ◽  
Transfer Measurement ◽  
Heat Transfer Measurement ◽  
Flux Sensor

Heat-transfer analysis in microfluidic devices is of great importance in applications such as micro-heat exchangers and microreactors. This work reports on improvements in temperature measurement techniques, which can be the source of large errors due to their intrusiveness and the unreliability of conventional thermal sensors. Gold thin films were deposited on a borosilicate substrate to realize a 2D heat flux sensor for heat-transfer measurement along the main flow within microchannels. Two applications are shown, one related to micro-heat exchangers and the other to microreactors. For the micro-heat exchanger, the effect of length scale on heat transfer in a straight microchannel was investigated and the validity of macroscale correlations for convective heat transfer was checked for deionized water flowing in microchannels of heights 12 to 52 μm. For the microreactor, the reaction enthalpy of an acid–base reaction measured using the new heat-flux sensor had only a 5% discrepancy from the standard value, showing the efficiency of the new thin-film device.

scholarly journals Comparative study on steady and unsteady heat transfer analysis of a spherical element using air/water mist two-phase flow

2020 ◽  
pp. 55-55
Author(s):  
Akram Abed ◽  
Sergey Shcheklein ◽  
Valery Pakhaluev
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Surface Temperature ◽  
Transfer Rate ◽  
Water Mist ◽  
Heat Transfer Analysis ◽  
Phase Flow ◽  
Sphere Surface ◽  
Unsteady Heat Transfer ◽  
Two Phase

In this study, two approaches to investigating the process cooling of a heated sphere were performed using air as well as air/water mist two-phase flow. Steady-state and unsteady heat transfer analysis were compared in the terms of the average surface temperature and heat transfer rate between the sphere surfaces and the cooling fluid. When the Bi<0.1, the temperature variation inside sphere can be neglected and the wildly known lumped capacitance model can be applied to estimate the heat transfer coefficient by measuring the sphere surface temperature. The effect of the different factors such as the inlet Re numbers, surface temperature and water mist rate on heat transfer characteristics are examined. The experimental results showed that the presence of water mist leads to a significant increase in heat transfer rate over the use of air coolant alone. Also, the unsteady thermal behaviors of the water mist impingement on the heated surface and dynamic-state of cooling process changing over the sphere surface were analyzed experimentally based on the unsteady surface temperature measurements. The experimental results of the unsteady heat transfer were compared to the results obtained from steady-state estimation under the corresponding surface temperature of the sphere. Moreover, the new proposed empirical correlation for the Nusselt number based on the present experimental data are given for practical uses. Results reasonably agree well within ?3.8%.

Heat Transfer Analysis of Motorcycle Engine Cylinder Using CFD under Various Fin Geometries and Speed Condition

2014 ◽  
Vol 592-594 ◽  
pp. 1612-1616
Author(s):  
Amit Ranjan ◽  
D.H. Das
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Combustion Engine ◽  
Heat Transfer Analysis ◽  
Engine Cylinder ◽  
Wind Velocities ◽  
Fluent Software ◽  
Annular Fins ◽  
Better Than

In thisstudy, the heat transfer analysis of internal combustion engine of motorbike is performed with the various fin geometries. Generally rectangular fins are used for motorbike but still this fin geometry could be modified to increase the heat transfer rate.A numerical investigation is carried out for two geometries such as annular and wavy, of finned engine cylinder using CFD and the results are compared. Various experimental methods are presented in literature to see the effect of wind velocity, fin geometry and the ambient temperature on heat transfer rate. In the present paper an effort is made to study the effect of wind velocities and fins geometries on the heat transfer rate and simulation of the heat transfer using CFD. The models are generated in CATIA V5 and simulated in FLUENT software. The results show that the heat transfer rate and effectiveness of the wavy fins is better than for the annular fins.

3-D Quasi-Steady State Heat Transfer Analysis for an Air-Cooled Motorcycle Engine

2010 ◽  
Vol 129-131 ◽  
pp. 1322-1325 ◽  
Author(s):  
Jiin Yuh Jang ◽  
Jia Yan Wu ◽  
Shang Hua Tsai
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Cylinder Head ◽  
Transfer Rate ◽  
Heat Transfer Analysis ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Exhaust Valves ◽  
Motorcycle Engine ◽  
Good Agreement

This study presents heat transfer rate and temperature distributions for the prediction of each component in an air-cooled motorcycle engines. The 3-D finite element method was used to solve the temperature field and heat transfer rate for each component (intake valves, exhaust valves, piston, piston rings, cylinder head and cylinder) of motorcycle engine when the piston is in TDC and BDC. The results shows that the fractions of heat transfer rate for each component are as follows: intake valves 11％, exhaust valves 8％, cylinder head 21％, the piston 35％ and the cylinder 25％. And the temperature measurement value is in good agreement with experimental data within 20%.

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