Analysis of the performance of the shell and tube heat exchanger: Influence of the baffles and the position of fluid inlet and outlet

The constant need for heat exchangers that are easy to manufacture and maintain, and that have a standardized and already known manufacturing technology, has led to the fact that shell and tube heat exchangers are one of the most common devices used in the process industry. In this paper, the analytical and numerical models of the basic shell and heat exchanger have presented with dimensions of 3750 x 1000 mm and a nominal heat capacity of 410 kW. Using the flow simulation, the influence of different numbers and arrangement of baffles and the changing the position of the inlet and outlet of warmer fluid are considered. The temperatures of the fluids on the inlet and outlet are taken into account as the main parameters for heat exchanger performance. From obtained results, it can be concluded that with the increase in the number of baffles, the performance of the heat exchanger is increased. The position of the inlet and outlet of the warmer fluid greatly influence the heat exchanger performance.Publishe

The effects of whey and pumpkin seed oil on blood biochemical parameters of liver function and lipid profile in rats chronically drinking low concentrations of ethanol

We studied the effects of whey and pumpkin seed oil supplementation on the biochemical parameters in blood serum of male rats after chronic ad libitum alcohol consumption. The levels of AST, ALT, total bilirubin, ALP, LDH, triglycerides, total cholesterol, HDL, LDL, VLDL, triglyceride/HDL ratio, total cholesterol/HDL ratio (cholesterol ratio) and LDL/HDL ratio (index of atherosclerosis) were determined in rats after six weeks of treatment with: (i) ethanol (12% ethanol, ad libitum), (ii) whey (2 g/kg per day), (iii) pumpkin seed oil (2 mL/kg per day), (iv) both ethanol and whey, and (v) both ethanol and pumpkin seed oil. The results showed no changes in the levels of AST, ALT, total bilirubin, ALP, total cholesterol, HDL and VLDL in alcoholic rats when compared to the controls (fed with a standard laboratory diet ad libitum) and rats supplemented with whey and pumpkin seed oil. Our results suggest that alcohol consumption in small doses for 6 weeks changes lipid metabolism and significantly elevates the LDL/HDL ratio (index of atherosclerosis) but does not induce extensive liver damage. Ethanol consumption in our experimental conditions lowered the triglyceride level as well as the triglyceride/HDL ratio, suggesting lipid redistribution and the induction of some cardio-protective effect. However, ethanol induced a higher index of atherosclerosis. Pumpkin seed oil showed some protective potential in alcoholic rats by lowering the total cholesterol/HDL ratio, but it elevated the LDH. Whey consumption prevented elevation of the atherosclerosis index, pointing to its protective role, probably through the redistribution of lipids. However, whey in combination with ethanol elevated LDH