The research aimed to develop a high-efficiency plate-type heat exchanger for exhaust gas using computational fluid dynamics (CFD) thermal analysis based on the plate shape, and to identify the optimal shape. Following this, a water/air plate heat exchanger was manufactured, and its characteristics were studied experimentally. As the Re number increases on the gas (or air) side, the heat transfer rate increases significantly, whereas an increase in the Re number on the water side leads to a smaller increase in heat transfer. This is attributed to the larger convective heat resistance on the gas side, causing a substantial reduction in gas-side heat resistance as gas velocity increases, resulting in a considerable overall reduction in heat resistance. The fluid flow pressure drop showed similar results between the CFD calculations and experimental outcomes.

The purpose of this study is to experimentally figure out thermal performances of a newly developed wavy patterned heat plates(first heat plates) which are known to have better thermal performances than the conventional heat plates. Three types of products were made with high and low chevron angled plates. The test results show that overall heat transfer coefficients and pressure drops increased with flow rates and chevron angles just like other studies. Another purpose of this study is to find a way to reduce pressure drops while maintaining or even improving the heat transfer characteristics of the first heat plates. Research on optimization of the distribution area on the heat plate to achieve the even fluid distribution was conducted, and then the second heat plates were developed to reflect the research results. Another new three types of products with the second heat plates were manufactured and tested, too. The test results of the second heat plates were compared with those of the first heat plates to find out how the distribution area contributed to the thermal performances of the heat plates. The comparison showed that distribution area optimization could affect thermal performances of the high chevron angled plate positively, but the low chevron angled plate had little effect from the optimization. This is considered to be because the low chevron angled plate itself has a characteristic that the pressure drop is small.

A gasketed plate heat exchanger(GPHE) requires a much smaller installation space than a shell & tube heat exchanger because of its compact and good thermal performances. However, GPHEs have a disadvantage of being relatively vulnerable to high temperature and pressure due to rubber gaskets. To overcome a GPHEs’ disadvantage, Welded Block type Plate Heat Exchangers(WBPHE) have been developed. The flow pattern and heat transfer principle of WBPHE are very similar to GPHEs, so they are very compact and can be applied to high temperature and pressure. In this study, the structure and characteristics of WBPHE are briefly introduced, and its thermal performances were conducted experimentally using hot and cold water in the Reynolds number’s range from 5,500 to 10,000. Test results were compared with the experimental correlations of other researchers, which shows that significant deviations were noticed in the heat transfer coefficient predictions with a deviation range from 31% to 85%. The previous friction factor correlations also predicted the current results with big errors from 25% to 45%. These deviations are expected to be due to different chevron angles between previous studies and the current study, and also the end-plate effect is expected to be one of the potential causes that led to these deviations.

본 연구에서는 저온소성 코팅을 적용한 SUS 304 판을 사용하여 고가의 티타늄 판 대체에 대한 성능평가를 수행하였다. 전산유 동해석 결과, 저온소성 코팅을 적용한 SUS 304 판은 100 마이크론 두께의 코팅까지는 티타늄 판에 비해 더 뛰어난 열전달 성능을 보이는 것으로 나타났다. 실제 열교환기를 이용하여 열전달 성능에 대한 실험을 한 결과, 코팅을 적용한 SUS 304 판이 티타늄 판에 비해 더 우수 한 열전달 성능을 나타냄을 확인하였다. 또한 개방검사를 통해서 판의 부식 및 스케일 생성 정도를 확인하였을 때, 코팅을 적용한 SUS 304 판의 내부식 성능은 티타늄 판과 거의 동등하게 나타났으며, 해수에 의한 스케일의 생성 억제 효과는 코팅을 적용한 SUS 304 판에서 더욱 우수하게 나타났다.

A new plate heat exchanger for water-refrigeration systems such as chillers has been developed. Before forming, two stainless steel plates are placed on each other and connected by tig welding. To outline of the plate did the seam welding, in order to form the flow pass on the plate inside the spot welding used. After the plates have been welded, the plates are hydraulically inflated using pressure by water or nitrogen.The plate is made of an SUS plate of 1m×2m in length and 1.2mm in thickness and are fixed in the top of the water tank.As a result of these, it is concluded that the plate exhibits good cooling performance and the average cooling capacity is approximately 2.9RT/plate and the average coefficient of performance (COP) of chiller system is 3.16.