An Experimental Study on Effect of Twisted Tape on Performance of Plane Steel Tube and 550 Corrugated Steel Tube Double Pipe Heat Exchanger

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1 IJSRD - International Journal for Scientific Research & Development Vol. 6, Issue 05, 2018 ISSN (online): An Experimental Study on Effect of Twisted Tape on Performance of Plane Steel Tube and 550 Corrugated Steel Tube Double Pipe Heat Exchanger Shatrudhan Lal Kushwaha 1 Mr. Sanjay Kumar Singh 2 1 M.Tech Student 2 Associate Professor 1,2 Department of Mechanical Engineering 1,2 Sagar Institute of Science and Technology, Bhopal India Abstract The main aim of this comparative analysis is to determine effectiveness, over all heat transfer coefficient and number of transfer unit using a straight steel tube double pipe heat exchanger(dphe) with respect to 55 0 corrugated steel be DPHE without anything insert and 55 0 corrugated steel be DPHE with insert twisted tape half and full length. In current work the fluid to fluid heat exchange is taken into consideration, Most of the investigations on heat transfer coefficients are for constant wall temperature or constant heat flux. The effectiveness, overall heat transfer coefficient, effect of hot water flow rate on effectiveness of heat exchanger when cold water mass flow rate is kept constant. Here studied and compared for parallel flow and counter flow DPHE arrangement of Straight steel tube and 55 0 corrugated steel be DPHE without anything insert and 55 0 corrugated steel be DPHE with insert twisted tape half and full length. All readings were taken at steady state condition of heat exchanger. The result shows in the graphical representation for effectiveness, LMTD, NTU and over all heat transfer coefficient for parallel flow and counter flow arrangement. of heat exchanger is decreases when mass flow rate of hot fluid is below 45LPH and then increases in straight steel and to 55 0 corrugated steel be DPHE without anything insert and 55 0 corrugated steel be DPHE with insert twisted tape half and full length when hot water mass flow rate varies and cold water flow is fixed at 45LPH Key words:, LMTD, NTU and over All Heat I. INTRODUCTION A heat exchanger is equipment which transfers the heat energy from hot fluid to a cold fluid without direct contact of the fluids as a result of temperature gradient take place. The design procedure of heat exchangers is quite complicated, as it needs exact analysis of heat transfer rate, efficiency and pressure drop apart from issues such as long term performance and the economic aspect of the equipment. The steel tube heat exchanger with inside 55 0 corrugated Double pipe heat exchanger (DPHE) is a modified form of simple steel tube DPHE. This modification increase some thermal efficiency as compare to simple DPHE. This kind of heat exchanger is widely used in chemical, food, oil and gas industries. Heat transfer enhancement methods:- In general, heat transfer enhancement methods are of following three main categories: 1) Active method:- This method involves some external power input for the enhancement of heat transfer. Some examples of active methods include induced pulsation by cams and reciprocating plungers. 2) Passive method:- This method generally uses surface or geometrical modifications to the flow channel by incorporating inserts or additional devices. For example, inserts extra component, swirl flow devices, treated surface, rough surfaces, extended surfaces, displaced enhancement devices, coiled tubes, surface tension devices and additives for fluids 3) Compound method:- Combination of the above two methods, such a rough surface with a twisted tape swirl flow device, or rough surface with fluid vibration, rough surface with twisted tapes. It is focused on reviewing the passive methods in double pipe heat exchanger(dphe). II. PARAMETERS DEPENDS ON THE HEAT TRANSFER A. transfer [U]: The overall heat transfer coefficient is a measure of the overall ability of a series of conductive and convective barriers to transfer heat. transfer coefficient is the ratio of the heat transfer LMTD at unit area. q=uadt q= heat transfer rate (W) U= overall heat transfer rate (W/ (m 2.K)) A = heat transfer surface area (m 2 ) dt= LMTD (K) B. [ ] :- The effectiveness ( ), is the ratio between the actual heat transfer rate and the maximum heat transfer rate: =qact/qmax = effectiveness qact= actual heat transfer rate (W) qmax = maximum heat transfer rate (W) C. LMTD (logarithmic mean temperature difference) : We assumed that a generic heat exchanger has two ends (which we called A and B) at which the hot and cold streams enters or exit on either sides then the LMTD is defined by the logarithmic mean as follows LMTD = ΔTA ΔTB ln(δta/δtb) Where, ΔTA = temperature difference between two streams at A And ΔTB = temperature difference between two streams at B. D. NTU (number of transfer unit) It is used to calculate the rate of heat transfer in heat exchanger (especially counter flow exchanger) when there is insufficient information to calculate the log mean temperature difference. All rights reserved by 150

NTU method is used: NTU= UA/C min Where, U = overall heat transfer coefficient A= heat transfer area C min= minimum capacity of thermal energy.

Outer tube [G.I], 5) Heater, 6) Cold water source, 7) Flow measuring devices, 8) AC power supply, 9) Thermocouples.

various parameter of heater, motor and temperature indicator depend on it. It helps in smooth operation of electrical equipment. Fig.

Specifications of Parts: 1) Straight tube heat exchanger: Plain Steel tube heat exchanger consists of 10 mm inner and length 1.5meter plain tube.

outer tube and exit from top of other side of outer tube. Fig. 3.1.

water tank. This motor and stirrer arrangement is installed inside Fig. 3.1.

2 NTU method is used: NTU= UA/C min Where, U = overall heat transfer coefficient A= heat transfer area C min= minimum capacity of thermal energy. III. EXPERIMENTAL SETUP The set-up consisted of the following components: 1) Plain Steel Tube, 2) 55 0 corrugated Steel Tube 3) Twisted Inserts 4) Outer tube [G.I], 5) Heater, 6) Cold water source, 7) Flow measuring devices, 8) AC power supply, 9) Thermocouples. 10) Electrical heater fired hot water boiler Fig : Hot Water Tank 3) Control Panel: The control panel consist all circuit of the system, the various parameter of heater, motor and temperature indicator depend on it. It helps in smooth operation of electrical equipment. Fig. 3: Experimental Setup of Heat Exchanger A. Specifications of Parts: 1) Straight tube heat exchanger: Plain Steel tube heat exchanger consists of 10 mm inner and length 1.5meter plain tube. The hot water flow rate was measured and controlled with rotameter; similarly cold water through second rotameter enters at top of one side of outer tube and exit from top of other side of outer tube. Fig : Control Panel and Display Board 4) Motor and Stirrer Motor and Stirrer are used to produced swirl in the hot water which is kept in the hot water tank. This motor and stirrer arrangement is installed inside Fig : Double Pipe heat Exchanger (DPHE) Straight steel Tube 2) Hot Water Tank: Hot water tank is installed on the CI pipe steel frame on the left top corner. It is the source of hot water using electric heater for heat exchanger. Hot water tank is shown in figure. Fig : Motor & Stirrer TEFC Weather proof Electric Motor Power 3P 440V 50Hz RPM 1400 KW 0.18 Frame 63 Mounting Flange Mounted the hot tank. All rights reserved by 151

3 5) Boiler: Make of item. 1) Plate : - is 2062 m.s. plate 2) Tube : - tata / ti/ msl 3) Valve : - sant / atam /mahavir. 4) Pump : - standred 5) Pr. switch : - indfos/ standred 6) Contecters : - seimens/ l& t 7) Panel : - powder coated dust proof 8) Relay : - seimens/l&t 9) Pre. gauge : - arihant 10) Heater : - s.b.s 11) Safety valve : - sant / atam / mahavir 12) Ele. motor : - abb / crompton. a) Specification:- 1) Hot water Boiler: It is a 100L water capacity vertical cylindrical shaped boiler which consist a heater of capacity 9KW at bottom end, it also have inlet point for cold fluid and suction point for water pump, air vent at top side, blow down valve at bottom side, water level tube, float switch for heater safety, thermocouple for inside temp. Measurement, Top side man hole for boilers cleaning. Out of 100L capacity. Fig : Design and fabrication of boiler 2) Water circulation pump: One of hot water shifting pump supply with motor fitting in same base frame. its power consumption is just 0.5 HP and deliver hot water upto height of 6-24 m. 3) Heater Systems: one no. of immersion flanged type best quality heater. It has 9KW power by this we can get hot water of 60º-90ºC temp. In just minute we save our valuable time. 6) Specifications of plain tube heat exchanger : Table: 3.1.6: Specification of heat Exchanger Tube. IV. SAMPLE CALCULATIONS: Now as a sample calculation for plain steel tube counter flow heat exchanger is given below: Mass Mass Flow Flow Rate for Rate for Th Sr.no Th Hot Cold in Tc Tc out Water Water in out Here the specific heat of water is taken as 4.187KJ/Kg K, For hot and cold mass flow rates of m h = 15 LPH, And m c = 45 LPH Calculations for : ΔT h = = C ΔT c = = 5.9 Heat lost by hot water Q h = m h X C ph X ΔT h = 15 X4.187X1000X = W ed water, Qc = m c X C pc X ΔT c = 45 X4.187X1000X = W Qactual = Qh+Qc 2 = = W ϵ = Qactual ϵ= Qmax mhcpmin(thin tcin) ϵ = 15 X4.187X1000X( ) 3600 ϵ = Calculation of LMTD: LMTD = (Thin - Tcout) - (Thout - Tcin) (Thin - Tcout) ln (Thout - Tcin) ( ) - ( ) LMTD = ( ) ln ( ) LMTD = C Calculation for Overall Heat : Area of the tube Ao = πdl = Ao = m 2 Uo = Qactual A0 X LMTD Uo = X19.5 Uo = w/m 2 k Calculation for Number of transfer unit : NTU = U 0A 0 Cmin NTU = U 0A 0 (mcpmin ) NTU = V. RESULTS & DISCUSSION In this part, result find out from experimental observation for effectiveness, temperature difference, overall heat transfer coefficient, NTU and Heat transfer, due to hot water mass flow rates variation (when cold water mass flow rate is fixed at 45 LPH). All rights reserved by 152

4 Table: 5.1. Plane Steel Tube Heat Exchanger Without Insert When Cold Water is Fixed at 45 LPH In counter flow:- Observation table T Water rate ( o cold(inlet) C) ( o ( C) C) rate unit In parallel flow:- Observation table Water rate (inlet) rate unit Table: Corrugated Tube Heat Exchanger without Insert When Cold Water is Fixed at 45 LPH In counter flow:- Observation table Water rate (inlet) rate unit All rights reserved by 153

5 In parallel flow: - Observation table Water rate (inlet) rate unit Table: Corrugated Tube Heat Exchanger 2.5 full length Insert When Cold Water is Fixed at 45 LPH In counter flow:- Observation table Water rate (inlet) S.S. No. rate unit In parallel flow:- Observation table Water rate (inlet) All rights reserved by 154

6 rate unit Table: Corrugated tube 2.5 half-length Insert When Cold Water is Fixed at 45 LPH In counter flow: - Observation table Water rate of Cold water (inlet) rate unit In parallel flow:- Observation table Water rate (inlet) rate unit VI. GRAPH TABLE FOR VARIOUS CASES All rights reserved by 155

Graph: 5.1. Comparative analysis of effectiveness when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.

Comparative analysis of LMTD when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.

Comparative analysis of effectiveness when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.

7 Graph: 5.1. Comparative analysis of effectiveness when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in counter flow arrangement. Graph: 5.4. Comparative analysis of LMTD when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in parallel flow arrangement. Graph: 5.2. Comparative analysis of effectiveness when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in parallel flow arrangement. Graph: 5.5. Comparative analysis of transfer when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in counter flow arrangement. Graph: 5.3. Comparative analysis of LMTD when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in counter flow arrangement. Graph: 5.6. Comparative analysis of transfer when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in parallel flow arrangement All rights reserved by 156

Graph: 5.7. Comparative analysis of NTU when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.

8 Graph: 5.7. Comparative analysis of NTU when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in counter flow arrangement. Graph: 5.8. Comparative analysis of NTU when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in parallel flow arrangement. Graph: 5.9. Comparative analysis of heat transfer rate in cold fluid when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in counter flow arrangement Graph: Comparative analysis of heat transfer rate in cold fluid when cold water is constant at 45 LPH for Plane steel tube, 55 corrugated steel tube without inserts and 55 corrugated steel tube DPHE with 2.5 full & half length inserts in parallel flow arrangement. VII. CONCLUSION In this experimental analysis of a straight steel tube and 55 0 Corrugated Steel Tube Double Pipe Heat Exchanger for parallel and counter flow in heat transfer lab with experimental setup. In experimental setup shell dimensions was also same. The mass flow rates inside tube and outside tube were varied as well as parallel flow and counter flow arrangement. The effectiveness of heat exchanger significantly affected water flow rate and hot water flow rate. When cold water mass flow rate is fixed at 45 LPH and increases mass flow rate of hot water then effectiveness is gradually decreases at mass flow rate of hot water is 45LPH then increases with increase mass flow rate of hot water Corrugated Steel Tube with 2.5 pitch full length is insert in steel tube is more effective in all condition when counter flow and parallel flow. The maximum value of heat transfer rate was found in counter flow arrangement with 2.5 full length insert. The maximum value of effectiveness in counter flow arrangement in case of plane steel tube without insert, copper wire tube without insert and 2.5 half-length insert respectively. It was observed that the value of overall heat transfer coefficient increases with increase in volume flow rate of hot fluid and maximum value of overall heat transfer coefficient was found in case of 2.5 full length insert was 538 W/m 2 K. It was observed that the value of LMTD increases with increase in volume flow rate of hot fluid and maximum value of LMTD was observed in case of 55 0 corrugated steel tube without insert was c. and it was 10.8%, 8.2% and 13% greater than the value found in 2.5 half-length insert, 55 0 corrugated steel tube without insert and 2.5 full length insert respectively. REFERENCES [1] D.D Clarke, V.R Vasquez,W.B whiting,m.greiner,sunsitivity and Uncertanty analysis All rights reserved by 157

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Experimental study on heat transfer characteristics of horizontal concentric tube using twisted wire brush inserts

Experimental study on heat transfer characteristics of horizontal concentric tube using twisted wire brush inserts International Journal of Current Engineering and Technology E-ISSN 2277 416, P-ISSN 2347 5161 216 INPRESSCO, All Rights Reserved Available at http://inpressco.com/category/ijcet Research Article Experimental