The Generalized Lévêque Equation and its application to flat tubes without and with passive inserts

2021 ◽  
Vol 171 ◽  
pp. 121053
Author(s):  
Dirk Bertsche ◽  
Sebastian Meinicke ◽  
Paul Knipper ◽  
Konrad Dubil ◽  
Thomas Wetzel
Keyword(s):  
Flat Tubes

scholarly journals Comparison of a Novel Polymeric Hollow Fiber Heat Exchanger and a Commercially Available Metal Automotive Radiator

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1175
Author(s):  
Tereza Kroulíková ◽  
Tereza Kůdelová ◽  
Erik Bartuli ◽  
Jan Vančura ◽  
Ilya Astrouski
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Hollow Fiber ◽  
Pressure Loss ◽  
Air Flow ◽  
Performance Parameters ◽  
University Of Technology ◽  
Flat Tubes ◽  
And Performance ◽  
Louvered Fins

A novel heat exchanger for automotive applications developed by the Heat Transfer and Fluid Flow Laboratory at the Brno University of Technology, Czech Republic, is compared with a conventional commercially available metal radiator. The heat transfer surface of this heat exchanger is composed of polymeric hollow fibers made from polyamide 612 by DuPont (Zytel LC6159). The cross-section of the polymeric radiator is identical to the aluminum radiator (louvered fins on flat tubes) in a Skoda Octavia and measures 720 × 480 mm. The goal of the study is to compare the functionality and performance parameters of both radiators based on the results of tests in a calibrated air wind tunnel. During testing, both heat exchangers were tested in conventional conditions used for car radiators with different air flow and coolant (50% ethylene glycol) rates. The polymeric hollow fiber heat exchanger demonstrated about 20% higher thermal performance for the same air flow. The efficiency of the polymeric radiator was in the range 80–93% and the efficiency of the aluminum radiator was in the range 64–84%. The polymeric radiator is 30% lighter than its conventional metal competitor. Both tested radiators had very similar pressure loss on the liquid side, but the polymeric radiator featured higher air pressure loss.

Tip Growing Actuator with the Hose-Like Structure Aiming for Inspection on Narrow Terrain

2011 ◽  
Vol 5 (4) ◽  
pp. 516-522 ◽  
Author(s):  
Hideyuki Tsukagoshi ◽  
◽  
Nobuyuki Arai ◽  
Ichiro Kiryu ◽  
Ato Kitagawa
Keyword(s):  
Plant Growth ◽  
Growth Process ◽  
Maximum Speed ◽  
Flexible Hose ◽  
Head Unit ◽  
Flat Tubes ◽  
Outer Environment ◽  
The Way

This paper proposes a flexible hose-like fluid actuator to inspect narrow curved or bumpy terrain. The tip alone moves forward and the rest remains stationary, enabling the actuator to move smoothly without interfering with the outer environment – a concept based on the plant growth process. The actuator consists of multiple flexible flat tubes bent in the skin, whose bending point is involved in preventing fluid from passing through. The actuator can also steer the direction in which the tip lengthens, while the shape of the rest remains unchanged. Our Grow-hose-I prototype is 62 mm in diameter and grows at a maximum speed of 500 mm/s while producing a 45 N drive. The way of carrying a head unit equipped with a camera is discussed and feasibility of the actuator’s inspection on narrow terrain is demonstrated.

Disposable Robotic Finger Driven Pneumatically by Flat Tubes and a Hollow Link Mechanism

2020 ◽  
Vol 32 (5) ◽  
pp. 958-976
Author(s):  
Junya Tanaka ◽  
Nobuto Matsuhira ◽  
◽  
Keyword(s):  
Bearing Capacity ◽  
Thermal Processing ◽  
Robot Hand ◽  
Load Bearing Capacity ◽  
Object Shape ◽  
Joint Structure ◽  
Link Mechanism ◽  
Flat Tubes ◽  
Deformation Force ◽  
The Cost

We propose a robotic finger with an exoskeleton-type structure that bends and extends by the deformation force of flat tubes. Our objective is to realize a disposable robot hand for gripping unsanitary objects. To reduce the cost of disposing of the robotic finger, a commercially available cable carrier chain was used for the exoskeleton component, and the flat tubes used in the pneumatic actuator were prepared by thermal processing of a commercially available tube. The driving joint of the robotic finger consists of a hollow link mechanism and two flat tubes, which are respectively arranged inside the hollow link mechanism and at the joint boundary. The proposed joint structure achieves both smooth drivability and good load-bearing capacity. The developed robotic finger weighs approximately 85 g and generates a fingertip force of approximately 4 N when a pressure of 0.25 MPa is applied. Because the developed robotic finger is pneumatically driven, it conforms to the object shape and is compliant to external force. Verification of the mechanism demonstrated that the developed robotic finger is useful because it was able to grasp six types of assumed objects.

Design Method for Flat Geotextile Tubes filled with Inhomogeneous Slurry

2011 ◽  
Vol 261-263 ◽  
pp. 628-632 ◽  
Author(s):  
Cui Wang ◽  
Shu Wang Yan ◽  
Run Liu
Keyword(s):  
Iterative Procedure ◽  
Design Method ◽  
Tensile Force ◽  
Unit Weight ◽  
Dominant Factor ◽  
Tube Size ◽  
Geotextile Tube ◽  
Large Size ◽  
Flat Tubes ◽  
The Relationship

The circumference tensile force developed in the geotextile during filling the tube is the dominant factor to construct a safe dike. Based on the feature of flat tubes, a iterative procedure is programmed, with which the shape of the large size geotextile tube, as well as the relationship among the tube size, the pumping pressure, the unit weight of the slurry and the tensile stress developed in the geotextile during filing the tube can be determined. In the procedure, the inhomogeneousness induced by the soil grain sedimentation is also considered.

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