• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.12
• /
• pp.821-827
• /
• 2010

Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.

• Journal of Biosystems Engineering
• /
• v.24 no.4
• /
• pp.343-350
• /
• 1999

The ambient air is commonly used as low-temperature heat source for heat pump operation. However, the coefficient of performance(COP) of the air to water heat pump is decreased with the ambient air temperature drop. In this study to solve this problem, the AVACTHE(Automatic Variable Area Capillary Type Heat Exchanger) with 3 levels of heat exchange area(0, 1,495.4, 1,794.5$\textrm{cm}^2$)was installed in the refrigerant circuit of the heat pump. The AVACTHE effect on the performance of heat pump was tested with the ambient air temperature variation. The COP improvement of the heat pump could be achieved by the AVACTHE installation when below -5$^{\circ}C$ of the ambient air temperature.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.3
• /
• pp.421-429
• /
• 2008

Various kinds of ship are operated to transport cargo or passengers at sea in the world. Most of the important auxiliary machineries installed in those ships are fluid machineries such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified turbo and positive displacement pumps. This paper analyzes only positive displacement pumps. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, total pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on ship's type, this paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, pump kW/ME MCR, pump kW/GE kW under the conditions of seagoing and berthing according to ship's type.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.3
• /
• pp.27-36
• /
• 2004

A Numerical analysis has been used to predict the performance in the automotive water pump with double discharge single suction. The influence of parameters such as coolant flow rate, rotational speed, ratio of blade height and clearance has been investigated. Also, the prediction of hydraulic performances such as static pressure rise, shaft power, hydraulic power and pump efficiency is carried out on the water pump including an impeller and a volute casing. A full size water pump test bench has been developed to validate the CFD flow model. Discharge flow rate, suction pressure, discharge pressure, rotational speed and torque measurements are provided. Coolant temperature is 8$0^{\circ}C$, water tank pressure is 1 kgf/$\textrm{cm}^2$ and flow rates vary.

• 유체기계공업학회:학술대회논문집
• /
• 2000.12a
• /
• pp.45-49
• /
• 2000

Vibration and noise problem in a hydraulic system became one of very important factors in evaluating the performance of a hydraulic system. It is known that vibration and noise in a hydraulic system is directly related to flow pulsation in the hydraulic pump in the system. This study investigated a modeling and simulation technique for pulsating flow in a swash plate type axial piston pump. The key design factors of the pump related to flow pulsation phenomenon of the pump are the physical parameters for notches on the valve plate of the pump. By the numerical analysis, effects of the physical parameters of the notch on the flow pulsation was elucidated.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.434-440
• /
• 2000

This study is focused on the performance prediction and design of the centrifugal pump with optimum shape. Design and analysis of centrifugal pump rely on experience of designer due to many fluid mechanical and geometrical variables. In this study, a design method was developed with experimental factors and analysed the method by comparition with 2nd-order vortex panel method. Impeller is the most important component affecting the performance of the centrifugal pump. The predicted total head for three cases, of which designs were determined by this method, agrees well with a particular commercial pump. This study shows that satisfactory performance of an optimal pump shape can be obtained through the automatic design routine.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.4
• /
• pp.441-447
• /
• 1998

Motivated by a recent work, a fuzzy-power-controller(FPC) is designed for the relieving-horsepower control of output variable pump with electrical proportional valve and actually implemented on the industrial excavator. In order to calculate the output power of pump with input of FPC, a linear discrete time model of load system to pump is obtained and the result is applied to control the engine-pump coupled system by software without pressure and flow sensor. The FPC controls the engine and pump coupled system by relieving horsepower control according to the change of load and the running conditions in relieving horsepower control are selected by fuzzy inference engine. A case study is peformed through the construction of the control device and installation on the excavator. It shows that the relieving-horsepower control system with the FPC, as suggested in this paper, is superior to the conventional PID controllers. And also, the excavator, with the FPC, shows that the power-loss of the coupled system is reduced and the running speed of the hydraulic actuator is enhanced.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2012.06a
• /
• pp.129-129
• /
• 2012

Pumps are used widely in industry, the commercial sector and ships. A poorly selected pump or a pump that does not run at optimum design duty point is a classic symbol of wasted energy and money. It, therefore, becomes important to evaluate the efficiency of these pumps. This paper analyzes traditional technique and instrument to measure some parameters needed to calculate a pump efficiency. The pump efficiency measuring instrument (PEMI) was made and tested on real pump systems. It has been giver the accurate results compared with performance curve given by pump maker.

• International Journal of Fluid Machinery and Systems
• /
• v.4 no.1
• /
• pp.133-139
• /
• 2011

In this paper, Based on Two-dimensional Flow Theory, adopting quasi-orthogonal method and point-by-point integration method to design the impeller of the low specific speed centrifugal pump by code, and using RANS (Reynolds Averaged N-S) Equation with a standard k-${\varepsilon}$ two-equation turbulence model and log-law wall function to solve 3D turbulent flow field in the impeller of the low specific speed pump. An analysis of the influences of the blade profile on velocity distributions, pressure distributions and pump performance and the investigation of the flow regulation pattern in the impeller of the centrifugal pump are presented. And the result shows that this method can be used as a new way in low speed centrifugal pump impeller design.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.10
• /
• pp.56-62
• /
• 2021

In this study, a cavitation occurrence in a piston-pump inlet was investigated by simulating the pressure distribution, according to the inlet shape of a variable-displacement swash-plate piston pump that supplies high-pressure oil to control the hydraulic system of a marine engine. Two types of pump inlets with different shapes were cast into impression models, and the models were reverse-engineered by 3D scanning. Then, the hydraulic-pressure distribution was analyzed through finite-element analysis. The results of the analysis confirmed that cavitation occurs more easily in the inlet with a steeper slope during pump operation because the inlet pressure on the valve plate is lower than that of the other pump with a gentler inlet slope.