This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene gly...This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene glycol, the vapor pressure of which is much lower than that of water, as the solvent of the fluorescent dyes. A supersonic moisture chamber is used as the atomizer for seeding the tracer particles to be visualized. The proposed technique is applied to the measurement of the temperature distribution in a thermal vertical buoyant plume. The proposed two-color LIF thermometry is found to be very effective for the study of such a thermal structure, and it is well suited for measuring the temperature field of an airflow.展开更多
Ground source heat pump (GSHP) systems that use a direct expansion method?are expected to have higher energy-saving performance than conventional air conditioning systems. The heat transfer rate is evaluated by measur...Ground source heat pump (GSHP) systems that use a direct expansion method?are expected to have higher energy-saving performance than conventional air conditioning systems. The heat transfer rate is evaluated by measuring the temperature, humidity, and flow rate at the indoor unit of the GSHP system. However, it is difficult to evaluate the flow rate by measuring the flow velocity distribution at the outlet of the indoor unit. In this study, the Scanning PIV method is proposed to improve the accuracy of the flow rate measured by hot wire anemometers. The flow rates obtained by the hot wire anemometers were 60.6% and 15.2% higher than those from the PIV method during cooling and heating operation, respectively. Compensation formulas are generated using the results of the Scanning PIV method to correct the measurements from the hot wire anemometers. This compensation formula reduced the error generated by the nonuniformity of velocity distribution. It was 60.6% to 2.5% in cooling operation and 15.2% to 0.9% in heating operation, respectively. The compensation formulas were applied to evaluate the performance of a GSHP system, and the result shows that the GSHP system provides improved performance stability compared to traditional air conditioning systems.展开更多
This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied an...This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied and it was acceptable. The spatial resolution of the z-direction has much room for improvement by increasing the number of cameras. When applied to the velocity distribution measurement of a thermal vertical buoyant plume, the proposed 3D PIV method is found to be very effective for studying thermal structures and well suited for measuring the airflow velocity field.展开更多
文摘This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene glycol, the vapor pressure of which is much lower than that of water, as the solvent of the fluorescent dyes. A supersonic moisture chamber is used as the atomizer for seeding the tracer particles to be visualized. The proposed technique is applied to the measurement of the temperature distribution in a thermal vertical buoyant plume. The proposed two-color LIF thermometry is found to be very effective for the study of such a thermal structure, and it is well suited for measuring the temperature field of an airflow.
文摘Ground source heat pump (GSHP) systems that use a direct expansion method?are expected to have higher energy-saving performance than conventional air conditioning systems. The heat transfer rate is evaluated by measuring the temperature, humidity, and flow rate at the indoor unit of the GSHP system. However, it is difficult to evaluate the flow rate by measuring the flow velocity distribution at the outlet of the indoor unit. In this study, the Scanning PIV method is proposed to improve the accuracy of the flow rate measured by hot wire anemometers. The flow rates obtained by the hot wire anemometers were 60.6% and 15.2% higher than those from the PIV method during cooling and heating operation, respectively. Compensation formulas are generated using the results of the Scanning PIV method to correct the measurements from the hot wire anemometers. This compensation formula reduced the error generated by the nonuniformity of velocity distribution. It was 60.6% to 2.5% in cooling operation and 15.2% to 0.9% in heating operation, respectively. The compensation formulas were applied to evaluate the performance of a GSHP system, and the result shows that the GSHP system provides improved performance stability compared to traditional air conditioning systems.
文摘This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied and it was acceptable. The spatial resolution of the z-direction has much room for improvement by increasing the number of cameras. When applied to the velocity distribution measurement of a thermal vertical buoyant plume, the proposed 3D PIV method is found to be very effective for studying thermal structures and well suited for measuring the airflow velocity field.
