The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips,as it is characterised by excellent heat transfer ability and flexibility for miniaturi...The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips,as it is characterised by excellent heat transfer ability and flexibility for miniaturisation.To boost the application of PHP,reliable heat transfer performance evaluationmodels are especially important.In this paper,a heat transfer correlation was firstly proposed for closed PHP with various working fluids(water,ethanol,methanol,R123,acetone)based on collected experimental data.Dimensional analysis was used to group the parameters.It was shown that the average absolute deviation(AAD)and correlation coefficient(r)of the correlation were 40.67%and 0.7556,respectively.For 95%of the data,the prediction of thermal resistance and the temperature difference between evaporation and condensation section fell within 1.13K/Wand 40.76K,respectively.Meanwhile,an artificial neural networkmodelwas also proposed.The ANN model showed a better prediction accuracy with a mean square error(MSE)and correlation coefficient(r)of 7.88e-7 and 0.9821,respectively.展开更多
Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus. Mechanical support of the rings found inside squid suckers was studied by be...Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus. Mechanical support of the rings found inside squid suckers was studied by bending tests. Tensile tests were carried out to study the maximum possible sucking force produced by squid suckers based on the strength of sucker stalks, normalized by the sucking areas. The squid suckers were also directly tested to obtain sucking forces by a special testing ar- rangement. Inspired by the squid suckers, three types of sucker artefacts were developed for the arm skin of an octopus inspired robot. The first sucker artefact made of knitted nylon sheet reinforced silicone rubber has the same shape as the squid suckers. Like real squid suckers, this type of artefact also has a stalk that is connected to the arm skin and a ring to give radial support. The second design is a straight cylindrical structure with uniform wall thickness made of silicone rubber. One end of the cylinder is directly connected to the arm skin and the other end is open. The final design of the sucker has a cylindrical base and a concave meniscus top. The meniscus was formed naturally using the surface tension of silicone gel, which leads to a higher level of the liquid around the edge of a container. The wall thickness decreases towards the tip of the sucker opening. Sucking forces of all three types of sucker artefacts were measured. Advantages and disadvantages of each sucker type were discussed. The final design of suckers has been implemented to the arm skin prototypes.展开更多
基金This work is funded by National Natural Science Foundation of China(No.51906216).
文摘The pulsating heat pipe is a very promising heat dissipation device to address the challenge of higher heat-flux electronic chips,as it is characterised by excellent heat transfer ability and flexibility for miniaturisation.To boost the application of PHP,reliable heat transfer performance evaluationmodels are especially important.In this paper,a heat transfer correlation was firstly proposed for closed PHP with various working fluids(water,ethanol,methanol,R123,acetone)based on collected experimental data.Dimensional analysis was used to group the parameters.It was shown that the average absolute deviation(AAD)and correlation coefficient(r)of the correlation were 40.67%and 0.7556,respectively.For 95%of the data,the prediction of thermal resistance and the temperature difference between evaporation and condensation section fell within 1.13K/Wand 40.76K,respectively.Meanwhile,an artificial neural networkmodelwas also proposed.The ANN model showed a better prediction accuracy with a mean square error(MSE)and correlation coefficient(r)of 7.88e-7 and 0.9821,respectively.
文摘Biomechanical properties of squid suckers were studied to provide inspiration for the development of sucker artefacts for a robotic octopus. Mechanical support of the rings found inside squid suckers was studied by bending tests. Tensile tests were carried out to study the maximum possible sucking force produced by squid suckers based on the strength of sucker stalks, normalized by the sucking areas. The squid suckers were also directly tested to obtain sucking forces by a special testing ar- rangement. Inspired by the squid suckers, three types of sucker artefacts were developed for the arm skin of an octopus inspired robot. The first sucker artefact made of knitted nylon sheet reinforced silicone rubber has the same shape as the squid suckers. Like real squid suckers, this type of artefact also has a stalk that is connected to the arm skin and a ring to give radial support. The second design is a straight cylindrical structure with uniform wall thickness made of silicone rubber. One end of the cylinder is directly connected to the arm skin and the other end is open. The final design of the sucker has a cylindrical base and a concave meniscus top. The meniscus was formed naturally using the surface tension of silicone gel, which leads to a higher level of the liquid around the edge of a container. The wall thickness decreases towards the tip of the sucker opening. Sucking forces of all three types of sucker artefacts were measured. Advantages and disadvantages of each sucker type were discussed. The final design of suckers has been implemented to the arm skin prototypes.
