Fluid dispensing is a method by which fluid materials(such as epoxy,adhesive,and encapsulant) are delivered in a controlled manner in electronics packaging.Fluid jetting,derived from inkjet technology,is a noncontact,...Fluid dispensing is a method by which fluid materials(such as epoxy,adhesive,and encapsulant) are delivered in a controlled manner in electronics packaging.Fluid jetting,derived from inkjet technology,is a noncontact,data-driven fluid dispensing technology.But ideal fluid materials for packaging are usually high viscous,which is difficult to realize by traditional inkjet technology.In this paper,a mechanical micro-droplet jetting system for high viscosity fluid was proposed.It consists of dispensing valve,motion stage,temperature control subsystem,pneumatic subsystem,driving circuit for solenoid valve,and system control software.Performance of this system under various circumstances was studied by changing several parameters,including working temperature,stroke length,back pressure and drive pulse width.Tiny droplets of 0.35 mm in diameter were produced by stainless steel nozzle of 0.2 mm in diameter in the experimental study.展开更多
It is a key factor to increase heat transfer coefficien t of high viscosity fluid in the shell side for making a high performance cooler.T he heat transfer and flow resistance performance of trapezoid fin tube high vi...It is a key factor to increase heat transfer coefficien t of high viscosity fluid in the shell side for making a high performance cooler.T he heat transfer and flow resistance performance of trapezoid fin tube high visc osity fluid cooler with helical or segmental baffles were studied, and compared with the heat transfer coefficient of low-fin-tube cooler with segmental baffl es. Experimental results indicated that heat transfer film coefficient in the sh ell side of trapezoid fin tube cooler with entire helical baffles was 60% more h igher than that of low-fin-tube cooler with segmental baffles,and pressure dr op was lower by 40%. Heat transfer film coefficient in the shell side of trapezo id fin tube cooler with entire helical baffles was 20% more higher than that of trapezoid-fin tube cooler with segmental baffles, and pressure drop was lower b y 50%.Heat transfer film coefficient in the shell side of trapezoid fin tube coo ler with entire helical baffles was 10% higher than that of trapezoid fin tube c ooler with sectional helical baffles, and pressure drop was lower by 19%.Heat tr ansfer film coefficient in the shell side of trapezoid fin tube cooler with segm ental baffles was 30% more higher than that of low-fin-tube cooler with segmen tal baffles, and pressure drop remained unchanged.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50775087)
文摘Fluid dispensing is a method by which fluid materials(such as epoxy,adhesive,and encapsulant) are delivered in a controlled manner in electronics packaging.Fluid jetting,derived from inkjet technology,is a noncontact,data-driven fluid dispensing technology.But ideal fluid materials for packaging are usually high viscous,which is difficult to realize by traditional inkjet technology.In this paper,a mechanical micro-droplet jetting system for high viscosity fluid was proposed.It consists of dispensing valve,motion stage,temperature control subsystem,pneumatic subsystem,driving circuit for solenoid valve,and system control software.Performance of this system under various circumstances was studied by changing several parameters,including working temperature,stroke length,back pressure and drive pulse width.Tiny droplets of 0.35 mm in diameter were produced by stainless steel nozzle of 0.2 mm in diameter in the experimental study.
文摘It is a key factor to increase heat transfer coefficien t of high viscosity fluid in the shell side for making a high performance cooler.T he heat transfer and flow resistance performance of trapezoid fin tube high visc osity fluid cooler with helical or segmental baffles were studied, and compared with the heat transfer coefficient of low-fin-tube cooler with segmental baffl es. Experimental results indicated that heat transfer film coefficient in the sh ell side of trapezoid fin tube cooler with entire helical baffles was 60% more h igher than that of low-fin-tube cooler with segmental baffles,and pressure dr op was lower by 40%. Heat transfer film coefficient in the shell side of trapezo id fin tube cooler with entire helical baffles was 20% more higher than that of trapezoid-fin tube cooler with segmental baffles, and pressure drop was lower b y 50%.Heat transfer film coefficient in the shell side of trapezoid fin tube coo ler with entire helical baffles was 10% higher than that of trapezoid fin tube c ooler with sectional helical baffles, and pressure drop was lower by 19%.Heat tr ansfer film coefficient in the shell side of trapezoid fin tube cooler with segm ental baffles was 30% more higher than that of low-fin-tube cooler with segmen tal baffles, and pressure drop remained unchanged.