Preparation of heat balance sheet on Single-Cylinder Diesel Engine.

(HEAT BALANCE ON 4-STROKE 10 HP SINGLE CYLINDER DIESEL ENGINE)

Experiment No. : -4

Aim of the Experiment: –

Preparation of heat balance sheet on Single-Cylinder Diesel Engine.

Apparatus used: –

  1. UNI-INSTA 10 H.P. 4-stroke, single cylinder horizontal diesel engine
  2. Dial thermometers
  3. Speedometer fitted to engine
  4. Thermometer
  5. Stop watch

Theory: –

In order to draw a heat balance sheet for a diesel engine, a complete test must be made on the engine, while moving constant load(say full load),and measurement must be carried out for all quantity of heat and energy sifted or given out during the test. The fuel consumption rate must be measured and evaluated. I.H.P & B.H.P of the engine, temperature and quality of cooling water must be measured also the analysis and weight of the exhaust gases must be measured.

For commercial testing, the following items of energy balance will be enough to know the performance of the engine-

  1. The calorific value (or the heating value) of the fuel supplied per unit time is considered as the 100% of energy supply.
  2. Heat converted to B.H.P. for the same interval of time expressed as percentage of (1).
  3. Heat carried away by circulating water in the same interval of time expressed as percentage of (1).
  4. Heat carried away by exhaust gases in the same interval of time expressed as a percentage of (1).

Formulae Used: –

\[\color\green{(i)\;Torque\;{T}=}\] \[\color\red{9.81* W * R_{Effective}\;\; }\color\black{N-m;}\] \[\color\green{Where\; R_{Effective} = \dfrac{(D + d)}{2}}\] \[\color\green{ or}\] \[\color\red{ \dfrac{(D + t_{Belt})}{2}\;\;}\color\black{ m}\] \[\color\green{ and}\] \[\color\red{ W _{Load} = (S_1 – S_2) \;\;}\color\black{Kg}\] \[\;\] \[\;\] \[\;\] \[\color\green{(ii)\; Brake\; Power,\; (B.P)\; = }\] \[\color\red{\dfrac{2*\pi*N*T}{ 60000}}\;\;\color\black{KW}\] \[\color\green{ Where,\; N \;= \;rpm,}\] \[\color\green{\; T\; = \;Torque\;in\; N-m,}\] \[\;\] \[\;\] \[\;\] \[\color\green{(iii)\; Fuel\; Consumption,\; (m_f)\; =}\] \[\color\red{\dfrac{50\; ml * 10^{ -6} *ρ_{Fuel}}{t}}\;\;\color\black{ Kg/Sec}\] \[\color\green{Here; \;1 ml\; = 10^{-3}\; litres, \;}\] \[\color\green{and \;1000 litres\; = 1 m^{3}\; So \;1 ml \;= 10^{-6} m^{3}}\] \[\;\] \[\;\] \[\;\] \[\color\green{(iv)\; Heat\; energy\; available\; from \;the \;fuel\; brunt,\;}\] \[\color\red{ (Q_s) =m_f * C. V. * 3600}\;\;\color\black{ KJ/hr}\] \[\;\] \[\;\] \[\;\] \[\color\green{(v)\; Heat\; energy\; equivalent \;to\; output \;brake\; power,\; }\] \[\color\red{Q_{BP} = \;BP * 3600}\;\;\color\black{ KJ/hr}\] \[\;\] \[\;\] \[\;\] \[\color\green{(vi) \;Heat \;energy \;lost\; to\; engine\; cooling \;water,\; }\] \[\color\red{Q_{CW} =m_w * C_w (t_{wo} – t_{wi}) * 3600 }\;\;\color\black{KJ/hr}\] \[\;\] \[\;\] \[\;\] \[\color\green{(vii)\; Heat\; energy \;carried\; away\; by\; the\; exhaust\; gases,}\] \[\color\red{ Q_{EG} = m_{fg} * C_{fg} (t_{fg} – t_{air}) * 3600}\;\;\color\black{ KJ/hr}\] \[\color\green{Where\; C_d \;(Co-efficient\; of\; Discharge) \;=}\] \[\color\red{ 0.6,\; ρ _{Air} \;= \;\dfrac{(P_a * 102)}{R * T_a}}\color\black{ Kg/ m^3}\] \[\color\red{A_o \;(Area \;of\; Orifice)\; = \;\dfrac{\pi* d_o *2}{ 4}\; }\color\black{m^2}\] \[\color\red{P_1 \;= \;1.01325 \;}\;\;\color\black{Bar},\color\red{\; R \;= 0.287}\;\;\color\black{ KJ/Kg.K}\] \[\color\red{T_a = (t_a + 273) K,}\color\green{ t_a \;= \;Ambient\; Temperature\; °C}\] \[\;\] \[\;\] \[\;\] \[\color\green{(viii)\; Unaccounted \;heat\; energy\; loss,\;}\] \[\color\red{ Q_{Unaccounted }= Q_s – Q_{BP} + Q_{CW} + Q_{EG}}\;\;\color\black{ KJ/hr}\]

Procedure: –

1. Before starting the engine we checked the fuel supply, lubrication oil, and availability of cooling water.

2. We Set the dynamometer to zero load and ran the engine till it attained the working temperature and steady state condition.

3. Noted down the fuel consumption rate, Engine cooling water flow rate, inlet and outlet temperature of the engine cooling water, Exhaust gases cooling water flow rate, Air flow rate, and Air inlet temperature and Engine Speed.

4. Changed dynamometer load to 15 kg and let it attain the steady state condition. Noted down the fuel consumption rate, Engine cooling water flow rate, inlet and outlet temperature of the engine cooling water, Exhaust gases cooling water flow rate, Air flow rate, and Air inlet temperature and speed in each case.

5. Repeated the experiment at 30 kg constant speed.

6. Disengaged the dynamometer and stopped the engine.

7. Did the necessary calculations and prepared the heat balance sheet.

Observations: –

\[\color\green{Engine\; Speed, \;}\] \[\color\red{N = 500}\;\;\color\black{ rpm}\] \[\;\] \[\;\] \[\;\] \[\color\green{No.\; of\; Cylinders, }\] \[\color\red{n = 1}\;\;\color\black{ \;\;(Single)}\] \[\;\] \[\;\] \[\;\] \[\color\green{Calorific\; Value\; of\; Fuel,}\] \[\color\red{C.V.\; = 38,000\;\;}\color\black{ KJ/Kg}\] \[\;\] \[\;\] \[\;\] \[\color\green{Specific\;Heat \;of \;Water,}\] \[\color\red{Cw \;= 4.187\;\;}\color\black{ KJ/Kg.K}\] \[\;\] \[\;\] \[\;\] \[\color\green{Specific\;Heat\;of\; Exhaust \;Flue\; Gases}\] \[\color\red{ C_{fg} \;= 2.1\;\;}\color\black{ KJ/Kg.K}\] \[\;\] \[\;\] \[\;\] \[\color\green{Gas \;Constant,}\] \[\color\red{ R = 0.287\;\;}\color\black{ KJ/Kg.K}\] \[\;\] \[\;\] \[\;\] \[\color\green{Ambient\;Temperature,\;}\] \[\color\red{ t_a = 24\;\;}\color\black{^{o}C}\] \[\;\] \[\;\] \[\;\] \[\color\green{Atmospheric \;Pressure,}\] \[\color\red{P_a = 1.01325 \;\;}\color\black{Bar}\] \[\;\] \[\;\] \[\;\] \[\color\green{Orifice\; Diameter,}\] \[\color\red{d_o = 25 * 10^{-3}}\;\;\color\black{ m}\] \[\;\] \[\;\] \[\;\] \[\color\green{Co-efficient\; of\; Discharge,}\] \[\color\red{C_d = 0.6}\] \[\;\] \[\;\] \[\;\] \[\color\green{Density\;of\; fuel\; (Diesel), }\] \[\color\red{ρ_{Fuel} = 810 to 910 \;\;}\color\black{Kg/ m^3}\] \[\;\] \[\;\] \[\;\] \[\color\green{Density \;of\; Water,}\] \[\color\red{ρ_{water} = 1,000\;\;}\color\black{ Kg/ m^3}\] \[\;\] \[\;\] \[\;\] \[\color\green{Brake \;Drum\; Diameter,}\] \[\color\red{D = 181.5 * 10^{-3}\;\;}\color\black{ m}\]

Observations Table: –

Engine Speed N (rpm): 500 rpm (Constant in all cases)

Sl. No.Temperature of Circulating Water(0C)Temperature of Circulating Water to calorimeter(0C)Temperature of exhaust gas                         (0C)
 Inlet tempOutlet TempInletOutletBefore calorimeterAfter calorimeter
1.273227304628
2.273527335431
3.273827366433
Table- 2.1
Sl. No.Load(kg)Time (min)Fuel consumed (cm3)Water flow rate     (10-3m3)
Fuel Tank ReadingSpilled volumeFinal volumeFlow in engine cylinderFlowing in calorimeter
104.085050033.95.8
2153.505050013.83.1
3302.17505007.82
Table- 2.2

Calculations: –

\[\color\green{Engine\; speed,\;}\color\red{ N                               =500\; }\color\black{rpm}\] \[\color\green{No.\; of\; cylinders,\;}\color\red{n                           =1}\] \[\color\green{Calorific\;Value \;of \;fuel ,\;}\color\red{ (C.V.)            = 38000 }\color\black{\;kJ/Kg}\] \[\color\green{Specific\; Heat \;of \;water, }\color\red{\;C_{pw}                   = 4.187}\color\black{ \;kJ/kg.K}\] \[\color\green{Specific\; Heat\;of \;exhaust\; gases,\; }\color\red{C_{pg}=2.1}\color\black{\; kJ/kg.K}\] \[\color\green{Gas \;constant \;}\color\red{(R)                               =0.287}\color\black{\; kJ/kg.K}\] \[\color\green{Heat\; supplied \;by \;the\; fuel          }\color\red{   \; = 32406.8\;}\color\black{ kJ/hr}\] \[\color\green{Heat \;converted\; into\; useful\; work}\color\red{ \;= 3769.94}\color\black{\; kJ/hr}\] \[\color\green{Heat \;carried\; away\; by\; the\; circulating \;water }\color\red{\;= 9431.31\; }\color\black{kJ/hr}\] \[\color\green{Heat\; carried \;away\; by\; exhaust\; gas  \;  }\color\red{             = 8924.83 }\color\black{\;kJ/hr}\]

Result Table: –

Heat Energy Supplied  KJ/hr  %ageHeat Energy Consumed (Distribution)  KJ/hr  % age
        Heat Energy available from the fuel burnt    (a) Heat Energy equivalent to output brake power  3769.94  11.63
  32406.8   (b) Heat energy lost to engine cooling water  9431.31  29.11
    (c) Heat Energy carried away by the exhaust gases  8924.83  27.54
    (d) Unaccounted heat Energy Loss  10280.72  31.72
  Total  32406.8  100%  Total  32406.8  100%

Result: –

The balancing of the heat balance sheet confirms the theory through practical. We see that the heat supplied by fuel is equal to heat consumed in various forms (some difference due to experimental inaccuracy).

Conclusion: –

To be written by student.

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