Climate change,rising fuel prices,and fuel security are some challenges that have emerged and have grown worldwide.Therefore,to overcome these obstacles,highly efficient thermodynamic devices and heat recovery systems...Climate change,rising fuel prices,and fuel security are some challenges that have emerged and have grown worldwide.Therefore,to overcome these obstacles,highly efficient thermodynamic devices and heat recovery systems must be introduced.According to reports,much industrial waste heat is lost as flue gas from boilers,heating plants,etc.The primary objective of this study is to investigate and compare unary(Al_(2)O_(3))thermodynamically,binary with three different combinations of nanoparticles namely(Al_(2)O_(3)+TiO_(2),TiO_(2)+ZnO,Al_(2)O_(3)+ZnO)and ternary(Al_(2)O_(3)+TiO_(2)+ZnO)as a heat transfer fluid.Initially,three different types of binary nanofluids were prepared by dispersing two types of nanoparticles in individual trails,such as aluminum oxide,zinc oxide,and titanium dioxide in various combined concentrations(e.g.,2%,4%,and 6%)into the water as the base fluid,using an ultrasonicator to ensure uniform suspension.The operating parameters such as nanoparticle concentration and flow rate are varied to evaluate the performance of various hybrid nanofluids under counterflow configuration.The findings of this research indicate that the binary nanofluid Al_(2)O_(3)+ZnO exhibits the highest thermal performance factor(2.83),followed by the ternary nanofluid Al_(2)O_(3)+TiO_(2)+ZnO(0.828),with the lowest performance observed for the unary nanofluid Al_(2)O_(3)(0.799).This research highlights the need for advancement into novel nanomaterial combinations,optimization of required fluid properties,stability enhancement,and thermal performance to strengthen the utilization of hybrid nanofluids in heat exchangers.展开更多
The operating mechanism of the pulsating heat pipe （PHP） is not well understood and the present technology cannot predict required design parameters for a given task. The aim of research work presented in this paper...The operating mechanism of the pulsating heat pipe （PHP） is not well understood and the present technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand the operation regimes of the PHP through experimental investigations. A series of experiments were conducted on a closed loop PHP with 5 turns made of copper capillary tube of 2 mm in inner diameter. Two different working fluids viz. ethanol and acetone were employed. The operating characteristics were studied for the variation of heat input, filling ratio （FR） and inclination angle of the tested device. The results strongly demonstrate the effect of the filling ratio of the working fluid on the operational stability and heat transfer capability of the device. Important insight into the operational characteristics of PHP has been obtained.展开更多
文摘Climate change,rising fuel prices,and fuel security are some challenges that have emerged and have grown worldwide.Therefore,to overcome these obstacles,highly efficient thermodynamic devices and heat recovery systems must be introduced.According to reports,much industrial waste heat is lost as flue gas from boilers,heating plants,etc.The primary objective of this study is to investigate and compare unary(Al_(2)O_(3))thermodynamically,binary with three different combinations of nanoparticles namely(Al_(2)O_(3)+TiO_(2),TiO_(2)+ZnO,Al_(2)O_(3)+ZnO)and ternary(Al_(2)O_(3)+TiO_(2)+ZnO)as a heat transfer fluid.Initially,three different types of binary nanofluids were prepared by dispersing two types of nanoparticles in individual trails,such as aluminum oxide,zinc oxide,and titanium dioxide in various combined concentrations(e.g.,2%,4%,and 6%)into the water as the base fluid,using an ultrasonicator to ensure uniform suspension.The operating parameters such as nanoparticle concentration and flow rate are varied to evaluate the performance of various hybrid nanofluids under counterflow configuration.The findings of this research indicate that the binary nanofluid Al_(2)O_(3)+ZnO exhibits the highest thermal performance factor(2.83),followed by the ternary nanofluid Al_(2)O_(3)+TiO_(2)+ZnO(0.828),with the lowest performance observed for the unary nanofluid Al_(2)O_(3)(0.799).This research highlights the need for advancement into novel nanomaterial combinations,optimization of required fluid properties,stability enhancement,and thermal performance to strengthen the utilization of hybrid nanofluids in heat exchangers.
文摘The operating mechanism of the pulsating heat pipe （PHP） is not well understood and the present technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand the operation regimes of the PHP through experimental investigations. A series of experiments were conducted on a closed loop PHP with 5 turns made of copper capillary tube of 2 mm in inner diameter. Two different working fluids viz. ethanol and acetone were employed. The operating characteristics were studied for the variation of heat input, filling ratio （FR） and inclination angle of the tested device. The results strongly demonstrate the effect of the filling ratio of the working fluid on the operational stability and heat transfer capability of the device. Important insight into the operational characteristics of PHP has been obtained.
