Numerical analysis of laminar heat transfer performance of in-plane spiral ducts with various cross-sections at fixed cross-section area

2012 ◽  
Vol 55 (21-22) ◽  
pp. 5882-5890 ◽  
Author(s):  
Agus P. Sasmito ◽  
Jundika C. Kurnia ◽  
Weijie Wang ◽  
Sachin V. Jangam ◽  
Arun S. Mujumdar
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Cross Section Area ◽  
Section Area ◽  
Plane Spiral

Investigation of the Effect of Cross Section on the Convective Heat Transfer Performance of Nanoemulsion in Microchannel Heat Exchanger

2021 ◽  
Author(s):  
Takele Gameda ◽  
M. Mehdi Kabir ◽  
Jiajun Xu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cross Section ◽  
Cross Sections ◽  
Heat Transfer Performance ◽  
Operating Conditions ◽  
Transfer Performance ◽  
Heat Transfer Characteristics ◽  
Microchannel Heat Exchanger ◽  
Transfer Characteristics

Abstract The present study aims to numerically investigate the effect of cross section on the heat transfer performance of single-phase flow of Ethanol/Polyalphaolefin nanoemulsion fluid with ethanol concentrations of 8 wt.% in a microchannel heat exchanger. While the exterior geometry of the microchannels’ solid structure remains the same, four different cross sections of channels including: circular, upward semi-circular, rectangular, and trapezoidal, are designed with keeping the channels’ wetted perimeters, mass flow rate, and Reynolds number constant for comparison purposes. In the present study, the hydrodynamic and heat transfer characteristics, including local Nusselt number, heat transfer coefficient, and velocity profile, were investigated under a uniform wall heat flux boundary conditions within the laminar flow regime. The channel models of different cross sections were developed by the COMSOL-Multiphysics for numerical analysis. The heat transfer characteristics were then compared for different cross sections under the same operating conditions, and the effect of aspect ratio for rectangular and trapezoidal cross sections were also studied.

scholarly journals Load bearing capacity of thin-walled rectangular and I-shaped steel sections of short both empty and concrete-filled columns

2021 ◽  
Vol 15 (58) ◽  
pp. 77-85
Author(s):  
Amor Bouaricha ◽  
Naoual Handel ◽  
Aziza Boutouta ◽  
Sarah Djouimaa
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Load Capacity ◽  
Cross Sectional ◽  
Short Columns ◽  
Cross Section Area ◽  
Section Area ◽  
Specimen Height ◽  
Steel Sections ◽  
Thin Walled

In this experimental work, strength results obtained on short columns subjected to concentric loads are presented. The specimens used in the tests have made of cold-rolled, thin-walled steel. Twenty short columns of the same cross-section area and wall thickness have been tested as follows: 8 empty and 12 filled with ordinary concrete. In the aim to determine the column section geometry with the highest resistance, three different types of cross-sections have been compared: rectangular, I-shaped unreinforced and, reinforced with 100 mm spaced transversal links. The parameters studied are the specimen height and the cross-sectional steel geometry. The registered experimental results have been compared to the ultimate loads intended by Eurocode 3 for empty columns and by Eurocode 4 for compound columns. These results showed that a concrete-filled composite column had improved strength compared to the empty case. Among the three cross-section types, it has been found that I-section reinforced is the most resistant than the other two sections. Moreover, the load capacity and mode of failure have been influenced by the height of the column. Also, it had noted that the experimental strengths of the tested columns don’t agree well with the EC3 and EC4 results.

scholarly journals Exact Longitudinal Vibration Characteristics of Rods with Variable Cross-Sections

2011 ◽  
Vol 18 (4) ◽  
pp. 555-562 ◽  
Author(s):  
Bulent Yardimoglu ◽  
Levent Aydin
Keyword(s):  
Differential Equation ◽  
Cross Section ◽  
Cross Sections ◽  
Longitudinal Vibration ◽  
Transformation Method ◽  
Variable Cross ◽  
Cross Sectional ◽  
Cross Section Area ◽  
Section Area ◽  
Sinusoidal Functions

Longitudinal natural vibration frequencies of rods (or bars) with variable cross-sections are obtained from the exact solutions of differential equation of motion based on transformation method. For the rods having cross-section variations as power of the sinusoidal functions ofax+b, the differential equation is reduced to associated Legendre equation by using the appropriate transformations. Frequency equations of rods with certain cross-section area variations are found from the general solution of this equation for different boundary conditions. The present solutions are benchmarked by the solutions available in the literature for the special case of present cross-sectional variations. Moreover, the effects of cross-sectional area variations of rods on natural characteristics are studied with numerical examples.

scholarly journals AN EXPERIMENTAL INVESTIGATION OF SOIL LAYER COUPLING FAILURE CHARACTERISTICS ON NATURAL GRASSLAND BY PASSIVE SUBSOILER-TYPE OPENERS

2020 ◽  
pp. 49-58 ◽  
Author(s):  
Changbin He ◽  
Yong You ◽  
Decheng Wang ◽  
Hongjian Wu ◽  
Bingnan Ye
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Layer Structure ◽  
Soil Layer ◽  
Failure Characteristics ◽  
Design And Optimization ◽  
Cross Section Area ◽  
Section Area ◽  
Draft Force ◽  
Natural Grassland

Unclear soil layer coupling failure characteristics on natural grassland impeded the design and optimization of appropriate tillage tools. The coupling failure characteristics including surface disturbance and profile, disturbed cross-section area, soil over-turning rate, and coupling forces between the soil layer of natural grassland and selected passive subsoiler-type openers were investigated in this paper. Three single-shoot openers (i.e. CO, AO and WAO) and a test unit were designed, and furrow opening experiments under different working depths were conducted. Results showed that, along the passages, U-shaped disturbed cross-sections were usually created with soil-root clods overturned along the furrows. The roots were usually broken in a pulling or dragging way underground. Both disturbed cross-section area and draft force values increased with the working depth increasing linearly (R2≥0.93), contrary to the tendency of the specific draft force with the depth. Winged opener (i.e. WAO) had larger draft forces and disturbed soil layer cross-section areas than no-winged openers (i.e. AO and CO). The soil layer failure processes of the natural grassland were affected by its composite soil layer structure and the geometry parameters of the openers. The results provide original references for designing novel furrow openers applicable to improve degraded natural grassland.

scholarly journals Numerical study on heat transfer and flow resistance characteristics of multi-head twisted spiral tube

2021 ◽  
pp. 206-206
Author(s):  
Zhiqun Zheng ◽  
Fayi Yan ◽  
Lei Shi
Keyword(s):  
Heat Transfer ◽  
Numerical Calculation ◽  
Cross Section ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Smooth Tube ◽  
Transfer Performance ◽  
Spiral Tube ◽  
Inside Diameter ◽  
The Cross

A numerical calculation model of multihead twisted spiral tube (MTST) was established. In the range of Reynolds number from 5000 to 35000, the influence of different twisted structure on the flow and heat transfer characteristics of the MTST was studied by numerical calculation. Numerical calculation results indicate that the Nusselt number and friction coefficient increase with the increase in the ratio of outside and inside diameter of the cross-section, the increase in the number of twisted nodes, and the increase in the number of twisted spiral tube heads. Under the condition of the same spiral structure and the same hydraulic diameter, the heat transfer performance of the MTST is better than that of the spiral smooth tube. In addition, through artificial neural network (ANN) analysis, the ratio of outside and inside diameter of the cross-section, number of twisted nodes, and the number of twisted spiral tube heads were optimized to promote the comprehensive heat transfer performance. The performance evaluation criterion is the highest when the ratio of outside and inside diameter of the cross-section is 25/22.5, the number of twisted nodes is 3, and the number of twisted spiral tube heads is 3, which is 1.849 of the spiral smooth tube.

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