Hyung-Soo Lim

Performance Characteristics of Side Channel Type Regenerative Pumps

The performance of a regenerative pump is affected by many parameters, especially blade shape of impeller, leakage flow in the clearance and head losses at the inlet & outlet. An impeller with J-shape blade was designed and 5 times scale up model was tested at similarity conditions to evaluate the performance. Performance variations with clearance change were executed. The amounts of leakage flow through the clearance were estimated using the one-dimensional leakage flow models and analysis. Main leakage flow is generated through the gap between the impeller and casing. The inlet & outlet head losses were also estimated. Such corrections are very important to evaluate the final performance of the impeller and pump. Cavitation test was also performed at 1,200 rpm. NPSH of the regenerative pump was obtained and growth of cavity within blades was visualized.

Effectiveness of finger-marker for maintaining the correct compression point during paediatric resuscitation: A simulation study

Objective: High‐quality cardiopulmonary resuscitation is a significant factor for increasing the survival rate of paediatric patients. This study is to investigate the effectiveness of finger‐marker stickers for maintaining the correct compression point during simulated infant cardiopulmonary resuscitation (CPR). Methods: This crossover simulation study was conducted with 40 emergency physicians and paramedics at emergency departments of 2 tertiary hospitals. We used a remodeled infant CPR manikin developed to measure CPR quality indicators. After random coupling of participants (20 pairs), the pre‐group (10 pairs) performed conventional 2‐rescuer infant manikin CPR, then performed sticker‐applied CPR after 1 month. The post‐group (10 pairs) performed the process in the opposite order. The participants placed finger‐marker stickers to indicate the appropriate compression point before starting CPR. We compared accurate finger placement rates and other CPR quality indicators (compression depth, rate, complete chest recoil, and hands‐off time) with and without the finger‐marker sticker. Results: All finger‐marker stickers were correctly attached within 5 s (4.88 ± 1.28 s) of approaching the model. There were significant differences in the rate of correct finger compression position between conventional and sticker‐applied CPR (25.4% [IQRs 7.6–69.8] vs. 88.2% [IQRs 69.6–95.5], P < 0.001). Results did not differ according to sex, career, and job of the participants. There were no significant differences in mean compression rate, depth, hands‐off times, and rate of fully recoiled compression between the 2 groups. Conclusion: Finger‐marker stickers can be used to maintain correct finger positioning during 2‐rescuer infant manikin CPR.

Performance Evaluation of a Regenerative Pump of Small Size

Performance of a regenerative pump for automobile was tested and carefully corrected to obtain performance of the pump. Flow calculations are also performed in one vane to vane region of the impeller and side channel. Corrections of leakage loss and performance reduction in the transient regions at the inlet and outlet are discussed in the study. The calculated values are good coincident with the measured and corrected values near the design and high flow rates. The flow is very complex three dimensional with a strong radial vortex due to centrifugal force and an axial vortex due to re-circulating flow between the impeller and the side channel. Momentum exchange on the plane between the impeller and the side channel are evaluated to estimate viscous losses in the pump. The present study contributes to showing the capability of flow simulation of complex flow in the regenerative pump by comparing the calculated performance with the measured value.Copyright

200kW Turbine Development for Organic Rankine Cycle System

This paper presents the process of turbine development for Organic Rankine Cycle(ORC) system. Development of turbine for ORC system is hot issue in the electric generation market due to the characteristic of organic refrigerant which the evaporate temperature is lower than general refrigerant. Recently, the industry have an interest about ORC turbine development in Korea, and they presented numerous research results. In developing the turbine, several processes can be considered. However, there was few document about ORC turbine development because of the trade secret. This paper can be used as a reference in developing ORC turbine.

3 Dimensional Flow Analysis of Small Regenerative Pump

Performance of a regenerative pump is evaluated based on the calculated through flows using the CFX-TASCflow code. Flow calculations are performed in one vane to vane space of the impeller and side channel. The flow is very complex three dimensional with a strong radial vortex due to centrifugal force and an axial vortex due to re-circulating flow between the impeller and the side channel. Momentum exchange on the plane between the impeller and the side channel are evaluated to estimate design parameters and viscous losses in the pump. The present study contributes to showing the capability of flow simulation of complex flow in the regenerative pump by comparing the calculated performance with the measured value.