• 대한기계학회논문집B
• /
• 제25권4호
• /
• pp.561-571
• /
• 2001

The standard uncertainty of flowrate measurement is obtained by combining that of independent variables. Gravimetric and volumetric method were applied to determine the flowrate and the standard uncertainties of flowrate measurement by both methods were evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainties of determining the flowrate were estimated from the sensitivity coefficient and the standard uncertainty of independent variables. For practical application, the methods for evaluating and expressing uncertainty in flow measurement were discussed. It was found that the uncertainties of the weighing and time measurement in gravimetric method, the volume and time measurement in volumetric method have dominant influence on that of flowrate measurement. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of flowrate measurement is shown clearly.

• 한국가시화정보학회지
• /
• 제15권3호
• /
• pp.14-19
• /
• 2017

Increase of blood viscosity significantly changes the flow resistance and wall shear stress which are related with cardiovascular diseases. For measurement of blood viscosity, microfluidic method has proposed by monitoring pressure between sample and reference flows in the downstream of a microchannel with two inlets. However, it is difficult to apply this method to unknown flow conditions. To measure blood viscosity under unknown flow conditions, a microfluidic method based on micro particle image velocimetry(PIV) is proposed in this study. Flow rate in the microchannel was estimated by assuming velocity profiles represent mean value along channel depth. To demonstrate the measurement accuracy of flow rate, the flow rates measured at the upstream and downstream of a T-shaped microchannel were compared with injection flow rate. The present results indicate that blood viscosity could be reasonably estimated according to shear rate by measuring the interfacial width and flow rate of blood flow. This method would be useful for understanding the effects of hemorheological features on the cardiovascular diseases.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• pp.745-749
• /
• 2002

This paper is on the study of flow force compensating method of spool type valve. A simple flow force compensating method using stepped spool is presented in this paper. It is easy to manufacture stepped spool in the presented method because the shape of it is simple. The method has the merit that the size of valve need not be increased. Actuating force required for driving means of spool can be decreased by the compensation of flow force. The effect of presented method is predicted through CFD analysis. The prototypes of flow force compensating Direct Drive Servo-Valve where the result of CFD analysis is reflected are manufactured, and the measurement of flow force is carried out. It is known from the measurement that the effect of flow force compensation is very similar to from CFD analysis.

• 한국전자통신학회논문지
• /
• 제13권1호
• /
• pp.77-84
• /
• 2018

터빈유량계(Turbine flowmeter)는 유량 측정시 높은 정확도와 반복성을 위해 선택되지만 교정시의 표준 환경 조건과 현장에서의 환경 조건 차이로 다양한 측정 불확도 요인을 발생시킨다. 또한 교정된 측정값 외의 구간에서의 사용을 위해 신뢰성 높은 보간 기법(Interpolation method)이 필요하다. 따라서 본 논문에서는 유량 측정(Flow measurement) 신뢰성 향상을 위해 터빈유량계의 출력 신호의 정확한 측정과 교정된 결과값의 보간, 온도변화를 실시간 보정(correction)하는 장비를 설계 및 제작하고 성능 검증을 수행함으로 현장에서의 측정 신뢰도를 확보하였다.

• 대한기계학회논문집A
• /
• 제29권12권
• /
• pp.1615-1620
• /
• 2005

We present a novel flow-rate independent cell counter using a fixed control volume between double electrical sensing zones. The previous device based on the single electrical cell sensing in a given flow-rate requires an accurate fluid volume measurement or precision flow rate control. The present cell counter, however, offers the flow-rate independent method for the cell concentration measurement with counting cells in a fixed control volume of $22.9{\pm}0.98{\mu}{\ell}$. In the experimental study, using the RBC (Red Blood Cell), we have compared the measured RBC concentrations from the fabricated devices with those from Hemacytometer. The previous and present devices show the maximum errors of $20.3\%\;and\;16.1\%$, which are in the measurement error range of Hemacytometer (about $20\%$). The present device also shows the flow-rate independent performance at the constant flow-rates ($5{\mu}{\ell}/min$ and $10{\mu}{\ell}/min$) and the varying flow-rate (4, 2, and $4{\mu}{\ell}/min$). Therefore, we demonstrate that the present cell counter is a simple and automated method for the cell concentration measurement without requiring an accurate fluid measurement and precision flow-rate control.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제22권2호
• /
• pp.129-143
• /
• 2022

Background: Patient-controlled analgesia (PCA) has been widely used as an effective medical treatment for pain and for postoperative analgesia. However, improper dose errors in intravenous (IV) administration of narcotic analgesics from a PCA infusion pump can cause patient harm. Furthermore, opioid overdose is considered one of the highest risk factors for patients receiving pain medications. Therefore, accurate delivery of opioid analgesics is a critical function of PCA infusion pumps. Methods: We designed a microbalance method that consisted of a closed acrylic chamber containing a layer and an oil layer with an electronic balance. A commercially available infusion analyzer (IDA-5, Fluke Co., Everett, WA, USA) was used to measure the accuracy of the infusion flow rate from a commercially available smart PCA infusion pump (PS-1000, UNIMEDICS, Co., Ltd., Seoul, Korea) and compared with the results of the microbalance method. We evaluated the uncertainty of the flow rate measurement using the ISO guide (GUM:1995 part3). The battery life, delay time of the occlusion alarm, and bolus function of the PCA pump were also tested. Results: The microbalance method was good in the short-term 2 h measurement, and IDA-5 was good in the long-term 24 h measurement. The two measurement systems can complement each other in the case of the measurement time. Regarding battery performance, PS-1000 lasted approximately 5 days in a 1 ml/hr flow rate condition without recharging the battery. The occlusion pressure alarm delays of PS-1000 satisfied the conventional alarm threshold of occlusion pressure (300-800 mmHg). Average accuracy bolus volume was measured as 63%, 95%, and 98.5% with 0.1 ml, 1 ml, and 2 ml bolus volume presets, respectively. A 1 ml/hr flow rate measurement was evaluated as 2.08% of expanded uncertainty, with a 95% confidence level. Conclusion: PS-1000 showed a flow accuracy to be within the infusion pump standard, which is ± 5% of flow accuracy. Occlusion alarm of PS-1000 was quickly transmitted, resulting in better safety for patients receiving IV infusion of opioids. PS-1000 is sufficient for a portable smart PCA infusion pump.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
• /
• pp.161-166
• /
• 2003

It is the common features of the integral reactors that the main components of the RCS are installed within the reactor vessel, and so there are no any flow pipes connecting the coolant pumps or steam generators. Due to no any flow pipes, it is impossible to measure the differential pressure at the RCS of the integral reactors, and it also makes impossible measure the flow-rate of the reactor coolant. As a alternative method, the method by the measurement of coolant pump power has been introduced in this study. Up to now, we did not found out a precedent which the coolant pump power is used for the real-time flow-rate calculation at normal operation of the commercial nuclear power plants. The objective of the study is to embody the real-time flow-rate calculation method by the measurement of coolant pump power in an integral reactor. As a result of the study, we could theoretically reason that the capacity-head curve and capacity-shaft power curve around the rated capacity with the high specific-speeded axial flow pumps have each diagonally steep incline but show the similar shape. Also, we could confirm the above theoretical reasoning from the measured result of the pump motor inputs, So, it has been concluded that it is possible to calculate the real-time flow-rate by the measurement of pump motor inputs. In addition, the compensation for a above new method can be made by HBM being now used in the commercial nuclear power plants.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
• /
• pp.270-273
• /
• 1999

Circular dynamic stereo has special advantages as it enables a 3-D measurement using a single TV camera and also enables a high accurate measurement without a cumbersome calibration. Annular particle streaks are recorded using this system and the size of annular streaks directly concerns to the depth from TV camera. That is, the size of annular streaks is inversely proportional to the depth from the TV camera and the depth can be measured automatically by image processing technique. Overlapped streaks can be processed also by our method. The flow measurement in a water tank is one of the applications of our system. Tracer particles are introduced into the water in a flow measurement. Since the tracer particles flow with water, three-dimensional velocity distributions in the water tank can be obtained by measuring the all movement of tracer particles. Experimental results demonstrate the feasibility of our method.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권4호
• /
• pp.898-903
• /
• 2001

The particle image velocimetry with liquid crystal tracers is used for visualizing and analysis of the bubbly flow in a vertical temperature gradient. This method allows simultaneous measurement of velocity and temperature field at a given instant of time Quantitative data of velocity were obtained by applying the MQD technique to visualized image. The paper describes the method, and presents the transient velocity patterns of bubbly flow.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
• /
• pp.29-35
• /
• 1996

For the Reactor Coolant System(RCS) flow rate measurement by the secondary calorimetric heat balance method, the coolant temperature of the hot leg is needed. Several Resistance Temperature Detectors(RTD) are installed in the hot leg to measure the temperature, but the average value of RTDs does not correctly represent the energy-averaged(bulk) temperature because of the thermal stratification phenomenon. Therefore some correction is introduced to predict the bulk temperature, but the correction inevitably contains uncertainty because the stratification is not defined well quantitatively yet. Therefore a large uncertainty for the correction has been used for the conservative estimation. But unrealistically large uncertainty causes degradation of the measurement method and yields difficulty to meet the acceptance criterion in start-up flow measurement test. In this paper, an analytical estimation is made on the correction and the related uncertainty using the measured hot leg velocity profile of System 80 reactor flow model test and the measured temperatures of YGN 3&4 and PVNGS 1&2 start-up tests. The results reveal that the magnitude of the correction uncertainty is much smaller than that used in the previous design. Therefore, the confidence on the flow rate measurement method can be improved and the difficulty in start-up flow measurement test can be lessened if the smaller correction uncertainty obtained through this estimation is applied.